Regulatory Guide 8.13: Difference between revisions

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{{Adams
{{Adams
| number = ML003739505
| number = ML13350A220
| issue date = 06/30/1999
| issue date = 03/31/1975
| title = Instruction Concerning Prenatal Radiation Exposure
| title = Instruction Concerning Prenatal Radiation Exposure
| author name =  
| author name =  
| author affiliation = NRC/RES
| author affiliation = NRC/OSD
| addressee name =  
| addressee name =  
| addressee affiliation =  
| addressee affiliation =  
Line 10: Line 10:
| license number =  
| license number =  
| contact person =  
| contact person =  
| document report number = RG-8.13
| document report number = RG-8.013
| document type = Regulatory Guide
| document type = Regulatory Guide
| page count = 11
| page count = 4
}}
}}
{{#Wiki_filter:U.S. NUCLEAR REGULATORY COMMISSION                                                                                             Revision 3 June 1999 REGULATORY GUIDE
{{#Wiki_filter:... ! .....
                                            OFFICE OF NUCLEAR REGULATORY RESEARCH
Q ....
                                                                        REGULATORY GUIDE 8.13 (Draft was issued as DG-801 4)
M
                            INSTRUCTION CONCERNING PRENATAL RADIATION EXPOSURE
7r'
March 1975 U.S. NUCLEAR REGULATORY COMMISSION
RE Q U LAT
Y GWU DE
OFFICE OF STANDARDS DEVELOPMENT
REGULATORY GUIDE 8.13 INSTRUCTION CONCERNING PRENATAL RADIATION EXPOSURE


==A. INTRODUCTION==
==A. INTRODUCTION==
This regulatory guide is intended to provide infor The Code of Federal Regulations in 10 CFR Part                                           mation to pregnant women, and other personnel, to help
Section 19.12 of 10 CFR Part 19 states that all individuals working in or frequenting any portion of a restricted area must be instructed in the health pro- tection problcms associated with exposure to radioactive materials or radiation. This guide describes the instruc- tion that should be provided concerning biological risks to embryos or fetuses resulting from prenatal exposure.
  19, "Notices, Instructions and Reports to Workers: In                                            them make decisions regarding radiation exposure dur spection and Investigations," in Section 19.12, "In                                                ing pregnancy. This Regulatory Guide 8.13 supple structions to Workers," requires instruction in "the                                             ments Regulatory Guide 8.29, "Instruction Conceming health protection problems associated with exposure to                                           Risks from Occupational Radiation Exposure" (Ref.


radiation and/or radioactive material, in precautions or                                          1), which contains a broad discussion of the risks from procedures to minimize exposure, and in the purposes                                              exposure to ionizing radiation.
==B. DISCUSSION==
Since the Law of Bergonie and Tribondeau was published in 19061 it has been known that the sensitiv- ity of cells to radiation damage is related to their reproductive activity and inversely related to their degree of differentiation. It follows that children could W
.,,"
be expected to be more radiosensitive than adults, fetuses more radiosensitive than children, and embryos even more radiosensitive.


and functions of protective devices employed." The in structions must be "commensurate with potential ra                                                        Other sections of the NRC's regulations also speci diological health protection problems present in the                                               fy requirements for monitoring external and internal work place."                                                                                      occupational dose to a declared pregnant woman. In 10
This principle has long been a factor in the development of radiation exposure standard
                                                                                                    CFR 20.1502, "Conditions Requiring Individual Mon The Nuclear Regulatory Commission's (NRC's)
                                                                                                  itoring of External and Internal Occupational Dose," li regulations on radiation protection are specified in 10
                                                                                                  censees are required to monitor the occupational dose CFR Part 20, "Standards for Protection Against Radi to a declared pregnant woman, using an individual ation"; and 10 CFR 20.1208, "Dose to an Embryo/
                                                                                                  monitoring device, if it is likely that the declared preg Fetus," requires licensees to "ensure that the dose to an                                          nant woman will receive, from external sources, a deep embryo/fetus during the entire pregnancy, due to occu dose equivalent in excess of 0.1 rem (1 mSv). Accord pational exposure of a declared pregnant woman, does ing to Paragraph (e) of 10 CFR 20.2106, "Records of not exceed 0.5 rem (5 mSv)." Section 20.1208 also re Individual Monitoring Results," the licensee must quires licensees to "make efforts to avoid substantial maintain records of dose to an embryo/fetus if monitor variation above a uniform monthly exposure rate to a ing was required, and the records of dose to the embryo/
declared pregnant woman." A declared pregnant fetus must be kept with the records of dose to the de woman is defined in 10 CFR 20.1003 as a woman who clared pregnant woman. The declaration of pregnancy has voluntarily informed her employer, in writing, of must be kept on file, but may be maintained separately her pregnancy and the estimated date of conception.


from the dose records. The licensee must retain the re- USNRC REGULATORY GUIDES
====s. Section====
                                                                                                  The guides are issued in the following ten broad divisions Regulatory Guides are issued to describe and make available to the tion as methods acceptable to the NRC staff for implementing specific  public such informa parts of the Corn-  1. Power Reactors mission's regulations, techniques used by the staff in evaluating specific                                                                      6.  Products problems or pos-    2. Research and Test Reactors tulated accidents, and data needed by the NRC staff in its review of                                                                             7. Transportation applications for per- mits and licenses. Regulatory guides are not substitutes for regulations,                        3. Fuels and Materials Facilities and compliance                                                   
20.104 of 10 CFR Part 20 places different limits on minors than on adult workers. Specifically, it limits anyone under the age of 18 to exposures not exceeding
10% of the limits for adult workers.


===8. Occupational Health===
A special situation arises when an occupationally
                                                                                                  4.  Environmental and Siting                    9. Antitrust and Financial Review with them is not required. Methods and solutions different from those set out in the guides  5-  Materials and Plant Protection will be acceptable if they provide a basis forthe findings requisite to                                                                         10. General tinuance of a permit or license by the Commission.                       the issuance orcon Single copies of regulatory guides may be obtained free of charge by writing to the Repro This guide was issued after consideration of comments received from the public.
,
exposed woman is pregnant. Exposure of the abdomen
:
of such a worker to penetrating radiation from either external or internal sources would also involve exposure of the embtyo or fetus. Because a number of studies have indicated that the embryo or fetus, is more sensitive dthn an adult, particularly during the first three months Corjttes Rendus des Seances de I'Aeademie des Sciences. VoL
143, pp. 983-985, 1906.


mentsandsuggestionsforimprovementsintheseguidesareencouragedatalltimes, Corn-                    duction and Distribution Services Section, OCIO, U.S. Nuclear Regulatory Commission, and   Washington, DC 20555-0001. or by fax to (301)415-2289; or by guides will be revised as appropriate, to accommodate comments and to                                                                                                  e-mail to DISTRIBU
after conception, when a womaii may not be aware that she is pregnant, the National Council on Radiation Protection and Measurements (NCRP) recommended in its Report No. 39 that special precautions be taken to limit exposure when an occupationally expo'ed woman could be pregnant.
formation or experience.                                                        reflect new in- TION@NRC.GOV.


Issued guides may also be purchased from the National Written comments may be submitted to the Rules and Directives                                                                                              Technical Information Service Branch, ADM, U.S.      a standing order basis. Details on this service may be obtained by writing              on Nuclear Regulatory Commission, Washington, DC 20555-0001.                                                                                                                    NTIS, 5285 Port Royal Road, Springfield, VA 22161.
==C. REGULATORY POSITION==
Instruction to workers performed under § 19.12 should be given prior to assignment to work in a restricted area. In providing instruction about health protection problems associated with radiation exposure, female workers and those who may supervise or work with them should be given specific instruction about prenatal exposure risks to the developing embryo and fetus.


contained in Regulatory Guide 8.29 (Ref. 1), this infor quired form or record until the Commission terminates            mation may be included as part of the training required each pertinent license requiring the record.                      under 10 CFR 19.12.
The instruction should ensure that the employees understand:
1. That the NCRP has recommended holding prenatal occupational exposure to 0.5 rem or less during the entire period of gestation; and
2.


The information collections in this regulatory            2. Providing Instruction guide are covered by the requirements of 10 CFR Parts
The reasons for this recommendation.
19 or 20, which were approved by the Office of Man                        The occupational worker may be given a copy of agement and Budget, approval numbers 3150-0044 and                this guide with its Appendix, an explanation of the con
3150-0014, respectively. The NRC may not conduct or                tents of the guide, and an opportunity to ask questions sponsor, and a person is not required to respond to, a            and request additional information. The information in collection of information unless it displays a currently          this guide and Appendix should also be provided to any valid OMB control number.                                          worker or supervisor who may be affected by a declara tion of pregnancy or who may have to take some action


==B. DISCUSSION==
The instruction should include the information provided in the Appendix to this guide. It should be presented to the employee, her supervisors, and her co-workers both orally and in written form. Each person should be given an opportunity to ask questions, and each person should be asked to acknowledge in writing that the instruction has been received.
in response to such a declaration.


As discussed in Regulatory Guide 8.29 (Ref. 1),                    Classroom instruction may supplement the written exposure to any level of radiation is assumed to carry            information. If the licensee provides classroom instruc with it a certain amount of risk. In the absence of scien          tion, the instructor should have some knowledge of the tific certainty regarding the relationship between low            biological effects of radiation to be able to answer ques dose exposure and health effects, and as a conservative            tions that may go beyond the information provided in assumption for radiation protection purposes, the                  this guide. Videotaped presentations may be used for scientific community generally assumes that any expo              classroom instruction. Regardless of whether the li sure to ionizing radiation may cause undesirable bio              censee provides classroom training, the licensee should logical effects and that the likelihood of these effects in        give workers the opportunity to ask questions about in creases as the dose increases. At the occupational dose            formation contained in this Regulatory Guide 8.13. The limit for the whole body of 5 rem (50 mSv) per year, the            licensee may take credit for instruction that the worker risk is believed to be very low.                                  has received within the past year at other licensed facili ties or in other courses or training.
==D. IMPLEMENTATION==
The purpose of this section is to provide informa- don to licensees regarding the use of this guide.


The magnitude of risk of childhood cancer follow ing in utero exposure is uncertain in that both negative          3. Licensee's Policy on Declared Pregnant Women and positive studies have been reported. The data from                  The instruction provided should describe the li        L
uSNRC REGULATORY GUIDES
  these studies "are consistent with a lifetime cancer risk          censee's specific policy on declared pregnant women, resulting from exposure during gestation which is two              including how those policies may affect a woman's to three times that for the adult" (NCRP Report No.               work situation. In particular, the instruction should in
Comments should be Sent to the Seetelarv oft he Commissiaon. U S Nuttlest Aegelatony Catonrnition. WashingIton. VC. 20M.. Attention locketing ean Rflasototy Guides &to issued to desctibo and myake available to the oub) c
  116, Ref. 2). The NRC has reviewed the available                   clude a description of the licensee's policies, if any, that scientific literature and has concluded that the 0.5 rem          may affect the declared pregnant woman's work situa
5ef..  
  (5 mSv) limit specified in 10 CFR 20.1208 provides an              tion after she has filed a written declaration of pregnan adequate margin of protection for the embryo/fetus.               cy consistent with 10 CFR 20.1208.
Section.


This dose limit reflects the desire to limit the total life The instruction should also identify who to contact time risk of leukemia and other cancers associated with for additional information as well as identify who radiation exposure during pregnancy.
oIttehade &rceptebt. to the MAC staff of itmplemtenting Wo.Ct t iC parts of the Caommhl,acoon,
.#9tittions. to dtnefiteolt teCh.nose used by tif. rtaff in theh guidaes sansuediolthievoollaviglo Wod divisaons.


should receive the written declaration of pregnancy.
euroi soxsocf~c problems of ocislootetd accidents. or to provide guitdance ittý egol Coons Ae~viso"y Guide* era ..ot substitutes to, *.q..tht-onC. and COtv1-6til.t I
G. P,odoicts Wttt them, Is not ,acquired Mehd o ou.n ittfttot h~
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2. Research an Toll Roesor*"
I Transportation tthe guides rovtit be occeotabte It they ptoodo a bros, ilat the foondinis rosti ttle to
3 FUG128611od Meeloatt Vlcod4.0
11. Oecupat~ooa1 "*S~til shot uisi,&we a# lon~tinuance of a petnit or h~eipos by the Cammistsoon
4
1 o ~i Antitrust Ae,..i Commtittotn and sugge'stect'o for ttttpvereuthsnt t these 5.u'dws a


In order for a pregnant worker to take advantage of          The recipient of the woman's declaration may be identi the lower exposure limit and dose monitoring provi                  fied by name (e.g., John Smith), position (e.g., immedi sions specified in 10 CFR Part 20, the woman must de              ate supervisor, the radiation safety officer), or depart clare her pregnancy in writing to the licensee. A form            ment (e.g., the personnel department).
====t. encouteogtd ====
    letter for declaring pregnancy is provided in this guide
9 Moaterials and Ptessi Plotaee,,on
                                                                      4. Duration of Lower Dose Limits for the Embryo/
111. Genetal Sit 40l fit"@.
    or the licensee may use its own form letter for declaring              Fetus pregnancy. A separate written declaration should be submitted for each pregnancy.                                           The lower dose limit for the embryo/fetus should remain in effect until the woman withdraws the
end tedtvlls illo be fewined as sootoop.aft, to accommnodute eorn
~~fts "'d Ito JetlCt now tot01I'oreton of eleeenence Hooee'.er. commentt an Copies Of Published girdhes mew be obtained by woollen
*equest indicatin~g the tltri outdoe. ttece-ied viilithS.n l
400tov months Altm, t6 isuanarce. 0d1 be coer divisonsO devs,,., to the U S Nuclear Pogulostory Commsottton. Washington. D C
tl.,a~y~saut.teirelogot.n; the noead to, ust &..I, t",soon
20W. Alfttent11 Oeiftfor.Office ol SteAdordo Developmen~t C.


==C. REGULATORY POSITION==
ENCLOSURE I
declaration in writing or the woman is no longer preg
    1. Who Should Receive Instruction                                  nant. If a declaration of pregnancy is withdrawn, the dose limit for the embryo/fetus would apply only to the Female workers who require training under 10                  time from the estimated date of conception until the CFR 19.12 should be provided with the information                  time the declaration is withdrawn. If the declaration is contained in this guide. In addition to the information
                                                              8.13-2


not withdrawn, the written declaration may be consid                         
Except In those cases in which the licensee chooses to propose an alternative method for complying with the portion of the Commission's regulations previously specified, the methods described herein should be used after September 1, 1975, to instruct female employees working in or frequenting any portion of a restricted area, and -those who may supervise or work with such employees, concerning the health protection problems associated with prenatal radiation exposure.


==D. IMPLEMENTATION==
APPENDIX TO REGULATORY GUIDE 8.13 POSSIBLE HEALTH RISKS TO CHILDREN OF WOMEN
ered expired one year after submission.
WHO ARE EXPOSED TO RADIATION DURING PREGNANCY
.Some recent studies have shown that the risk of leukemia and other cancers in children increases if the mother Is exposed to a significant amount of radiation during pregnancy.


The purpose of this section is to provide informa
According to a report by the National Academy of Sciences, the incidence of leukemia among children under 10 years of age in the United States could rise from 3.7 cases in 10,000
5. Substantial Variations Above a Uniform Month tion to licensees and applicants regarding the NRC
children to 5.6 cases in 10,000 children if the children were exposed to I rem of radiation before birth (a
    ly Dose Rate                                                staff's plans for using this regulatory guide.
"rem" is a measure of radiation). The Academy has also estimated that an equal number of other types of cancers could result from this level of radiation.


Unless a licensee or an applicant proposes an ac According to 10 CFR 20.1208(b), "The licensee              ceptable alternative method for complying with the shall make efforts to avoid substantial variation above a      specified portions of the NRC's regulations, the meth uniform monthly exposure rate to a declared pregnant            ods described in this guide will be used by the NRC
tuthough other scientific studies have shown a much smaller effect from radiation, the Nuclear Regulatory Commission wants women employees of its licensees to be aware of any possible risk so that the women can take steps they think appropriate to protect their offspring.
woman so as to satisfy the limit in paragraph (a) of this      staff in the evaluation of instructions to workers on the section," that is, 0.5 rem (5 mSv) to the embryo/fetus.        radiation exposure of pregnant women.


The National Council on Radiation Protection and REFERENCES
As an employee of a Nuclear Regulatory Commis- Sion licensee, you may be exposed to more radiation than the general public. However, the Nuclear Regula- tory Commission has established a basic exposure limit for all occupationally exposed adults of 1.25 reins per calendar quarter, or 5 reins per year. No clinical evidence of harm would be expected in an adult working within these levels for a lifetime. Because the risks of undesir- able effects may be greater for young p)eople, persons under 18.years of age are permitted to be exposed to only 10 percent of the adu!. occupational limits. (This lower limit is also applied to members of the general public.)
Measurements (NCRP) recommends a monthly equiv alent dose limit of 0.05 rem (0.5 mSv) to the embryo/
The scientific organization called the National Council on Radiation Protection and Measurements has recommended that because unborn babies may be more sensitive to radiation than adults, their radiation dose as a result of occupational exposure of the mother should not exceed 0.5 rem. Other scientific groups, including the International Commission on Radiation Protection, have also stressed the need to keep radiation doses to unborn children as low as practicable.
                                                                1.     USNRC, "Instruction Concerning Risks from Oc fetus once the pregnancy is known (Ref. 2). In view of cupational Radiation Exposure," Regulatory the NCRP recommendation, any monthly dose of less Guide 8.29, Revision 1, February 1996.


than 0.1 rem (1 mSv) may be considered as not a sub stantial variation above a uniform monthly dose rate            2.     National Council on Radiation Protection and and as such will not require licensee justification. How              Measurements, Limitation of Exposure to Ioniz ever, a monthly dose greater than 0.1 rem (1 mSv)                      ing Radiation, NCRP Report No. 116, Bethesda, should be justified by the licensee.                                  MD, 1993.
All Nuclear Regulatory Cornnii&sion li'ensees are now required* to inform all Individuals who work in a
*By Title 10. Part 19 of the Code of Federai Regulations.


8.13-3
restricted area of the health protection problems asso- ciated with radiation exposure. This instruction would in many cases include information on the possible risks to unborn babies. The regulations also state*
that licensees should keep radiation exposures as low as practicable. According to the National Council on Radiation Protection and Measurements, particular efforts should be made to keep the radiation exposure of an embryo or fetus at the very lowest practicable level during the entire period of pregnancy.


APPENDIX
Thus it is the responsibility of your employer to take all practicable steps to reduce your radiation exposure. Then it is your responsibility to decide whether the exposure you are receiving is sufficiently low to protect your unborn child. The advice of your employer's health physicist or radiation protection officer should be obtained to determine whether radia- tion levels in your working areas are high enough that a baby could receive 0.5 rem or more before birth. If so, the alternatives that you might want to consider are:
      QUESTIONS AND ANSWERS CONCERNING PRENATAL RADIATION EXPOSURE
(a) If you are now pregnant or expect to be soon, you could decide not to accept or continue assignments in these areas.
1. Why am I receiving this information?                      not be able to have some emergency response I
      The NRC's regulations (in 10 CFR 19.12, "Instruc        responsibilities.


tions to Workers") require that licensees instruct indi        4. Why do the regulations have a lower dose limit viduals working with licensed radioactive materials in             for the embryo/fetus of a declared pregnant radiation protection as appropriate for the situation.            woman than for a pregnant worker who has not The instruction below describes information that occu              declared?
(b) You could reduce your exposure, where possible, by decreasing the amount of time you spend in the radiation area, increasing your distance from the radiation source, and using shielding.
pational workers and their supervisors should know A lower dose limit for the embryo/fetus of a de about the radiation exposure of the embryo/fetus of            clared pregnant woman is based on a consideration of pregnant women.


greater sensitivity to radiation of the embryo/fetus and The regulations allow a pregnant woman to decide        the involuntary nature of the exposure. Several scientif whether she wants to formally declare her pregnancy to       ic advisory groups have recommended (References 1 take advantage of lower dose limits for the embryo/            and 2) that the dose to the embryo/fetus be limited to a fetus. This instruction provides information to help          fraction of the occupational dose limit.
(c) If you do become pregnant, you could ask your employer to reassign you to areas involving less exposure to radiation. If this is not possible, you might consider leaving your job. If you decide to take such steps, do so without delay. The unborn child is most sensitive to radiation during the first three months of your preg.


women make an informed decision whether to declare a          5. What are the potentially harmful effects of radi pregnancy.                                                        ation exposure to my embryo/fetus?
nancy.
2. If I become pregnant, am I required to declare                  The occurrence and severity of health effects my pregnancy?                                            caused by ionizing radiation are dependent upon the No. The choice whether to declare your pregnancy        type and total dose of radiation received, as well as the is completely voluntary. If you choose to declare your        time period over which the exposure was received. See pregnancy, you must do so in writing and a lower radi        Regulatory Guide 8.29, "Instruction Concerning Risks ation dose limit will apply to your embryo/fetus. If you      from Occupational Exposure" (Ref. 3), for more infor choose not to declare your pregnancy, you and your            mation. The main concern is embryo/fetal susceptibil      I
embryo/fetus will continue to be subject to the same          ity to the harmful effects of radiation such as cancer.


radiation dose limits that apply to other occupational        6. Are there any risks of genetic defects?
(d) You could delay having children until you are no longer working in an area where the radiation dose to your unborn baby could exceed 0.5 rem.
workers.


Although radiation injury has been induced experi
"In Title 10, Part 20.
3. If I declare my pregnancy in writing, what                mentally in rodents and insects, and in the experiments happens?                                                  was transmitted and became manifest as hereditary dis orders in their offspring, radiation has not been identi If you choose to declare your pregnancy in writing, fied as a cause of such effect in humans. Therefore, the the licensee must take measures to limit the dose to risk of genetic effects attributable to radiation exposure your embryo/fetus to 0.5 rem (5 millisievert) during the is speculative. For example, no genetic effects have entire pregnancy. This is one-tenth of the dose that an been documented in any of the Japanese atomic bomb occupational worker may receive in a year. If you have survivors, their children, or their grandchildren.


already received a dose exceeding 0.5 rem (5 mSv) in the period between conception and the declaration of          7. What if I decide that I do not want any radiation your pregnancy, an additional dose of 0.05 rem (0.5              exposure at all during my pregnancy?
8.13-2
mSv) is allowed during the remainder of the pregnancy.              You may ask your employer for a job that does not In addition, 10 CFR 20.1208, "Dose to an Embryo/              involve any exposure at all to occupational radiation Fetus," requires licensees to make efforts to avoid sub      dose, but your employer is not obligated to provide you stantial variation above a uniform monthly dose rate so      with ajob involving no radiation exposure. Even if you that all the 0.5 rem (5 mSv) allowed dose does not occur      receive no occupational exposure at all, your embryo/
in a short period during the pregnancy.                      fetus will receive some radiation dose (on average 75 This may mean that, if you declare your pregnancy,      mrem (0.75 mSv)) during your pregnancy from natural the licensee may not permit you to do some of your nor        background radiation.


mal job functions if those functions would have al                  The NRC has reviewed the available scientific lit lowed you to receive more than 0.5 rem, and you may          erature and concluded that the 0.5 rem (5 mSv) limit
-
                                                      8.13-4
------------
You may also, of course, choose to:
(e) Continue working in the higher radiation areas, but with full awareness that you are doing so at some small increased risk for your unborn child.


provides an adequate margin of protection for the                 10. To declare my pregnancy, do I have to have doc embryo/fetus. This dose limit reflects the desire to lim                umented medical proof that I am pregnant?
The following facts should be noted to help you make a decision:
it the total lifetime risk of leukemia and other cancers.
1. The first three months of pregnancy are the most important, so you should make your decision quickly.


NRC regulations do not require that you provide If this dose limit is exceeded, the total lifetime risk of medical proof of your pregnancy. However, NRC regu cancer to the embryo/fetus may increase incrementally.
2.


lations do not preclude the licensee from requesting However, the decision on what level of risk to accept is medical documentation of your pregnancy, especially yours. More detailed information on potential risk to if a change in your duties is necessary in order to com the embryo/fetus from radiation exposure can be found ply with the 0.5 rem (5 mSv) dose limit.
At the present occupational exposure limit, the actual risk to the unborn baby is small, but experts disagree on the exact amount of risk.


in References 2-10.
3.


11. Can I tell the licensee orally rather than in writ
There is no need to be concerned about sterility or loss of your ability to bear children. The radiation dose required to produce such effects is more than 100
8. What effect will formally declaring my pregnan                      ing that I am pregnant?
times larger than the Nuclear Regulatory Commission's dose limits for adults.
      cy have on my job status?
                                                                        No. The regulations require that the declaration Only the licensee can tell you what effect a written      must be in writing.


declaration of pregnancy will have on your job status.            12. If I have not declared my pregnancy in writing, As part of your radiation safety training, the licensee                but the licensee suspects that I am pregnant, do should tell you the company's policies with respect to                the lower dose limits apply?
4.
the job status of declared pregnant women. In addition, before you declare your pregnancy, you may want to                    No. The lower dose limits for pregnant women ap talk to your supervisor or your radiation safety officer        ply only if you have declared your pregnancy in writ and ask what a declaration of pregnancy would mean              ing. The United States Supreme Court has ruled (in specifically for you and your job status.                        United Automobile Workers International Union v.


Johnson Controls,Inc., 1991) that "Decisions about the In many cases you can continue in your present job        welfare of future children must be left to the parents with no change and still meet the dose limit for the             who conceive, bear, support, and raise them rather than embryo/fetus. For example, most commercial power                to the employers who hire those parents" (Reference 7).
Even if you work in an area where you receive only 0.5 rem per three-month period, in nine months you could receive 1.5 reins, which exceeds the full-term limit suggested by the NCRP. Therefore, if you d&cide to restrict your unborn baby's exposure as recommended by the NCRP, be aware that the 0.5 rem limit applies to
reactor workers (approximately 93%) receive, in 12              The Supreme Court also ruled that your employer may months, occupational radiation doses that are less than          not restrict you from a specific job "because of concerns
*
0.5 rem (5 mSv) (Ref. 11). The licensee may also con            about the next generation." Thus, the lower limits ap sider the likelihood of increased radiation exposures            ply only if you choose to declare your pregnancy in from accidents and abnormal events before making a                writing.
the full nine-month pregnancy.


decision to allow you to continue in your present job.            13. If I am planning to become pregnant but am not yet pregnant and I inform the licensee of that in If your current work might cause the dose to your writing, do the lower dose limits apply?
**
embryo/fetus to exceed 0.5 rem (5 mSv), the licensee has various options. It is possible that the licensee can              No. The requirement for lower limits applies only and will make a reasonable accommodation that will al            if you declare in writing that you are already pregnant.
The remainder of this document contains a brief explanation of radiation and its effects on humans. As you will see, some radiation is present everywhere and the levels of radiation most employees of Nuclear Regulatory Commission licensees receive are not much larger than these natural levels. Because the radiation levels in the facility where you will be working are required by law to be kept quite low, there is not considered to be a significant health risk to individual adult employees.


low you to continue performing your current job, for example, by having another qualified employee do a                14. What if I have a miscarriage or find out that I
0.072 rem per year. The average dose from one chest X-ray is 0.045 rem.
                                                                        am not pregnant?
small part of the job that accounts for some of your radi ation exposure.                                                         If you have declared your pregnancy in writing, you should promptly inform the licensee in writing that
9. What information must I provide in my written                  you are no longer pregnant. However, if you have not declaration of pregnancy?                                    formally declared your pregnancy in writing, you need not inform the licensee of your nonpregnant status.


You should provide, in writing, your name, a decla ration that you are pregnant, the estimated date of              15. How long is the lower dose limit in effect?
Radiation can also be received from natural sources such as rock or brick structures, front consumer pro- ducts such as television and glow-in-the-dark watches, and from air travel. The possible annual dose from working 8 hours a day near a granite wall at the Redcap Stand in Grand Central Station, New York City, is 0.2 rem, and the average annual dose in the United States from TV, consumer products, and air travel is 0.0026 rem.
conception (only the month and year need be given),                     The dose to the embryo/fetus must be limited until and the date that you give the letter to the licensee. A          you withdraw your declaration in writing or you inform form letter that you can use is included at the end of            the licensee in writing that you are no longer pregnant.


these questions and answers. You may use that letter,             If the declaration is not withdrawn, the written decla use a form letter the licensee has provided to you, or            ration may be considered expired one year after write your own letter.                                            submission.
Radiation, like many things, can be harmful. A large dose to the whole body (such as 600 reins in one day)
would probably cause death in about 30 days, but such large doses result only from rare accidents. Control of exposure to radiation is based on the assumption that any exposure, no matter how small, involves some risk.


8.13-5
The occupational exposure limits are set so low, how- ever, that medical evidence gathered over the past 50
years indicates no clinically observable injuries to indi- viduals due to radiation exposures when the established radiation limits are not exceeded. This was true even for exposures received under the early occupational ex- posure limits, which were many times higher than the present limits. Thus the risk to individuals at the occupational exposure levels is considered to be very low. However, it is impossible to say that the risk is zero.


16. If I have declared my pregnancy in writing, can          on radiation risks. The licensee should be able to give I revoke my declaration of pregnancy even if I          this document to you.
To decrease the risk still further, licensees are expected to keep actual exposures as far below the limits as practicable.


am still pregnant?
The current exposure limits for people working with radiation have been developed and carefully reviewed by nationally and internationally recognized groups of scientists. It must be remembered, however, that these limits are for adults. Special consideration is appropriate when the person being exposed is, or may be, an expectant mother, because the exposure of an unborn child may also be involved.
                                                                  For information on legal aspects, see Reference 7, Yes, you may. The choice is entirely yours. If you      "The Rock and the Hard Place: Employer Liability to revoke your declaration of pregnancy, the lower dose          Fertile or Pregnant Employees and Their Unborn Chil limit for the embryo/fetus no longer applies.                 dren-What Can the Employer Do?" which is an article in the journal Radiation ProtectionManagement.


17. What if I work under contract at a licensed You may telephone the NRC Headquarters at (301)
Prenatal Irradiation The prediction that an unborn child would be more sensitive to radiation than an adult is supported by observations for relatively large doses.
    facility?
                                                              415-7000. Legal questions should be directed to the The regulations state that you should formally de        Office of the General Counsel, and technical questions clare your pregnancy to the licensee in writing. The li      should be directed to the Division of Industrial and censee has the responsibility to limit the dose to the        Medical Nuclear Safety.


embryo/fetus.                                                     You may also telephone the NRC Regional Offices at the following numbers: Region I, (610) 337-5000;
Large doses delivered before birth alter both physical development and behavior in experimentally exposed animals. A
18. Where can I get additional information?
report of the National Academy of Sciences states that short-term doses in the range of 10 to 20 reins cause subtle changes In the nerve cells of unborn and infant rats. The report also states, however, that no radiation- induced changes in development have been demon- strated to result In experimental animals from doses up to about I rem per day extended over a large part of the period before birth.
                                                              Region II, (404) 562-4400; Region III, (630) 829-9500;
    The references to this Appendix contain helpful in       and Region IV, (817) 860-8100. Legal questions should formation, especially Reference 3, NRC's Regulatory          be directed to the Regional Counsel, and technical Guide 8.29, "Instruction Concerning Risks from Occu          questions should be directed to the Division of Nuclear pational Radiation Exposure," for general information        Materials Safety.


8.13-6
The National Academy of Sciences also noted that doses of 25 to 50 reins to a pregnant human may cause Discussion of Radiation The amount of radiation a person receives is called the "dose"
and is measured in "reins." The average peron in the United States gets a dose of one rem from natural sources every 12 years. The dose from natural radiation is higher in some states, such as Colorado, Wyoming, and South Dakota, primarily because of cosmic. radiation. There the average person gets one rem every 8 years.


REFERENCES FOR APPENDIX
Natural background radiation levels are also much higher in certain local areas. A dose of one rem may be received in some areas on the beach at Guarapari, Brazil, in only about 9 days, and some people in Kerala, India, get a dose of one rem every 5 months.
1.     National Council on Radiation Protection and                              6.      R. Doll and R. Wakeford, "Risk of Childhood Measurements, Limitation of Exposure to Ioniz                                      Cancer from Fetal Irradiation," The BritishJour ing Radiation, NCRP Report No. 116, Bethesda,                                     nal of Radiology, 70, 130-139, 1997.


MD, 1993.
Many people receive additional radiation for medical reasons. The annual radiation dose averaged over the United States population from diagnostic X.rays is
'C
8.13-3


7.     David Wiedis, Donald E. Jose, and Timm 0.
growth disturbances in her offspring. Such doses sub.


2.     International Commission on Radiological                                          Phoebe, "The Rock and the Hard Place: Employ Protection, 1990 Recommendations of the Inter                                      er Liability to Fertile or Pregnant Employees and national Commission on Radiological Protec                                        Their Unborn Children-What Can the Employer tion, ICRP Publication 60, Ann. ICRP 21: No.                                      Do?" Radiation Protection Management, 11,
stantially exceed. of course, the maximum permissible occupational exposure limits.
        1-3, Pergamon Press, Oxford, UK, 1991.                                            41-49, January/February 1994.


3.     USNRC, "Instruction Concerning Risks from                                  8.      National Council on Radiation Protection and Occupational Radiation Exposure," Regulatory                                      Measurements, Considerations Regarding the Guide 8.29, Revision 1, February 1996.1 (Elec                                      Unintended Radiation Exposure of the Embryo, tronically available at www.nrc.gov/NRC/RG/                                        Fetus,orNursingChild,NCRP Commentary No.
Concern about prenatal exposure (i.e., exposure of a child while in its mother's uterus) at the permissible occupational levels is primarily based on the possibility that cancer (especially leukemia) may develop during the first 10 years of the child's life. Several studies have been performed to evaluate this risk. One study involved the followup of 77.000 children exposed to radiation before birth (because of diagnostic abdominal X-rays made for medical purposes during their mother's pregnancy).
Another stud)y involved the followup of 20.000 such children.


index.html)                                                                        9, Bethesda, MD, 1994.
In addition,
1292 children who received prenatal exposure during the bombing of Hiroshima and Nagasaki were studied. Although contradictory results have been obtained, most of the evidence sugests a relationship between prenatal exposure and an increased risk of childhood cancer.


4.     Committee on the Biological Effects of Ionizing                            9.      National Council on Radiation Protection and Radiations, National Research Council, Health                                      Measurements, Risk Estimates for Radiation Effects of Exposure to Low Levels of Ionizing                                      Protection, NCRP Report No. 115, Bethesda, Radiation (BEIR V), National Academy Press,                                        MD, 1993.
Summary Occupational exposures to radiation arc being kept low. flowever, qualified scientists have recommended that the radiation dose to a pregn,,.nt woman should not exceed 0.5 rem because of possible risks to her unborn child. Since this 0.5 rem is lower than the dose generally permitted to adult workers, women may want to take special actions to avoid receiving higher exposures, just as they might stop smoking during pregnancy or might climb stairs more carefully to reduce possible risks to their unborn children.


Washington, DC, 1990.
Bibliography Donald G. Pizzarello and Richard L. Witcofski, Basic Radiation Biology, Philadelphia: Lea and Febizer. 1967.


10. National Radiological Protection Board, Advice
2.
5.      United Nations Scientific Committee on the Ef                                      on Exposure to lonising RadiationDuringPreg fects of Atomic Radiation, Sources andEffects of                                  nancy, National Radiological Protection Board, Ionizing Radiation, United Nations, New York,                                      Chilton, Didcot, UK, 1998.


1993.
National Academy of Sciences - National Research Council, The Effccts on Populations of Exposure to Low Levels of Ioni:ing Radiation, Washington, D.C., November 1972.


11.    M.L. Thomas and D. Hagemeyer, "Occupational Radiation Exposure at Commercial Nuclear Pow er Reactors and Other Facilities, 1996," Twenty
3.
'Single copies of regulatory guides, both active and draft, and draft                    Ninth Annual Report, NUREG-0713, Vol. 18, NUREG documents may be obtained free of charge by writing the                          USNRC, 1998.2 Reproduction and Distribution Services Section, OCIO, USNRC,
  Washington, DC 20555-0001, or by fax to (301)415-2289, or by                    2 email to <DISTRIBUTION@NRC.GOV>. Active guides may also                            Copies are available at current rates from the U.S. Government be purchased from the National Technical Information Service on a                  Printing Office, P.O. Box 37082, Washington, DC 20402- 9328 (tele standing order basis. Details on this service may be obtained by writ              phone (202)512-1800); or from the National Technical Information ing NTIS, 5285 Port Royal Road, Springfield, VA 22161. Copies of                  Service by writing NTIS at 5285 Port Royal Road, Springfield, VA
  active and draft guides are available for inspection or copyingfor a fee          22161. Copies are available for inspection or copying for a fee from from the NRC Public Document Room at 2120 L Street NW, Wash                        the NRC Public Document Room at 2120 LStreet NW, Washington, ington, DC; the PDR's mailing address is Mail Stop LL-6, Washing                  DC; the PDR's mailing address is Mail Stop LL-6, Washington, DC
  ton, DC 20555; telephone (202)634-3273: fax (202)634-3343.                        20555; telephone (202)634-3273; fax (202)634-3343.


8.13-7
National Council on Radiation Protection and Measurements. Basic Radiation Protection Criteria, NCRP Report No. 39, Washington, D.C., January
15, 1971.


FORM LETTER FOR DECLARING PREGNANCY
4.
      This form letter is provided for your convenience. To make your written declaration of pregnancy, you may fill in the blanks in this form letter, you may use a form letter the licensee has provided to you, or you may write your own letter.


DECLARATION OF PREGNANCY
United Nations. Ionizing Radiation: Levels and Effects, 2 vol., Reports of the United Nations Scientific Committee on the Effects of Atomic Radiation, Report No. A/8725, United Nations.
To:
      In accordance with the NRC's regulations at 10 CFR 20.1208, "Dose to an Embryo/Fetus," I am declaring that I am pregnant. I believe I became pregnant in                                (only the month and year need be provided).
      I understand the radiation dose to my embryo/fetus during my entire pregnancy will not be allowed to ex ceed 0.5 rem (5 millisievert) (unless that dose has already been exceeded between the time of conception and submitting this letter). I also understand that meeting the lower dose limit may require a change in job or job responsibilities during my pregnancy.


(Your signature)
New York, 1972.
                                                        (Your name printed)                                        I
                                                        (Date)
                                                    8.13-8


REGULATORY ANALYSIS
5.
    A separate regulatory analysis was not prepared for this regulatory guide. A regulatory analysis prepared for 10 CFR Part 20, "Standards for Protection Against Radiation" (56 FR 23360), provides the regulatory ba sis for this guide and examines the costs and benefits of the rule as imple mented by the guide. A copy of the "Regulatory Analysis for the Revision of 10 CFR Part 20" (PNL-6712, November 1988) is available for inspec tion and copying for a fee at the NRC Public Document Room, 2120 L
Street NW, Washington, DC, as an enclosure to Part 20 (56 FR 23360).
                                  8.13-9


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US. Atomic Energy Commission, Division of Technical Information, Understanding the Atom Series:
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Instruction Concerning Prenatal Radiation Exposure
ML13350A220
Person / Time
Issue date: 03/31/1975
From:
NRC/OSD
To:
References
RG-8.013
Download: ML13350A220 (4)
v • d • e


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March 1975 U.S. NUCLEAR REGULATORY COMMISSION

RE Q U LAT

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OFFICE OF STANDARDS DEVELOPMENT

REGULATORY GUIDE 8.13 INSTRUCTION CONCERNING PRENATAL RADIATION EXPOSURE

A. INTRODUCTION

Section 19.12 of 10 CFR Part 19 states that all individuals working in or frequenting any portion of a restricted area must be instructed in the health pro- tection problcms associated with exposure to radioactive materials or radiation. This guide describes the instruc- tion that should be provided concerning biological risks to embryos or fetuses resulting from prenatal exposure.

B. DISCUSSION

Since the Law of Bergonie and Tribondeau was published in 19061 it has been known that the sensitiv- ity of cells to radiation damage is related to their reproductive activity and inversely related to their degree of differentiation. It follows that children could W

.,,"

be expected to be more radiosensitive than adults, fetuses more radiosensitive than children, and embryos even more radiosensitive.

This principle has long been a factor in the development of radiation exposure standard

s. Section

20.104 of 10 CFR Part 20 places different limits on minors than on adult workers. Specifically, it limits anyone under the age of 18 to exposures not exceeding

10% of the limits for adult workers.

A special situation arises when an occupationally

,

exposed woman is pregnant. Exposure of the abdomen

of such a worker to penetrating radiation from either external or internal sources would also involve exposure of the embtyo or fetus. Because a number of studies have indicated that the embryo or fetus, is more sensitive dthn an adult, particularly during the first three months Corjttes Rendus des Seances de I'Aeademie des Sciences. VoL

143, pp. 983-985, 1906.

after conception, when a womaii may not be aware that she is pregnant, the National Council on Radiation Protection and Measurements (NCRP) recommended in its Report No. 39 that special precautions be taken to limit exposure when an occupationally expo'ed woman could be pregnant.

C. REGULATORY POSITION

Instruction to workers performed under § 19.12 should be given prior to assignment to work in a restricted area. In providing instruction about health protection problems associated with radiation exposure, female workers and those who may supervise or work with them should be given specific instruction about prenatal exposure risks to the developing embryo and fetus.

The instruction should ensure that the employees understand:

1. That the NCRP has recommended holding prenatal occupational exposure to 0.5 rem or less during the entire period of gestation; and

2.

The reasons for this recommendation.

The instruction should include the information provided in the Appendix to this guide. It should be presented to the employee, her supervisors, and her co-workers both orally and in written form. Each person should be given an opportunity to ask questions, and each person should be asked to acknowledge in writing that the instruction has been received.

D. IMPLEMENTATION

The purpose of this section is to provide informa- don to licensees regarding the use of this guide.

uSNRC REGULATORY GUIDES

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ENCLOSURE I

Except In those cases in which the licensee chooses to propose an alternative method for complying with the portion of the Commission's regulations previously specified, the methods described herein should be used after September 1, 1975, to instruct female employees working in or frequenting any portion of a restricted area, and -those who may supervise or work with such employees, concerning the health protection problems associated with prenatal radiation exposure.

APPENDIX TO REGULATORY GUIDE 8.13 POSSIBLE HEALTH RISKS TO CHILDREN OF WOMEN

WHO ARE EXPOSED TO RADIATION DURING PREGNANCY

.Some recent studies have shown that the risk of leukemia and other cancers in children increases if the mother Is exposed to a significant amount of radiation during pregnancy.

According to a report by the National Academy of Sciences, the incidence of leukemia among children under 10 years of age in the United States could rise from 3.7 cases in 10,000

children to 5.6 cases in 10,000 children if the children were exposed to I rem of radiation before birth (a

"rem" is a measure of radiation). The Academy has also estimated that an equal number of other types of cancers could result from this level of radiation.

tuthough other scientific studies have shown a much smaller effect from radiation, the Nuclear Regulatory Commission wants women employees of its licensees to be aware of any possible risk so that the women can take steps they think appropriate to protect their offspring.

As an employee of a Nuclear Regulatory Commis- Sion licensee, you may be exposed to more radiation than the general public. However, the Nuclear Regula- tory Commission has established a basic exposure limit for all occupationally exposed adults of 1.25 reins per calendar quarter, or 5 reins per year. No clinical evidence of harm would be expected in an adult working within these levels for a lifetime. Because the risks of undesir- able effects may be greater for young p)eople, persons under 18.years of age are permitted to be exposed to only 10 percent of the adu!. occupational limits. (This lower limit is also applied to members of the general public.)

The scientific organization called the National Council on Radiation Protection and Measurements has recommended that because unborn babies may be more sensitive to radiation than adults, their radiation dose as a result of occupational exposure of the mother should not exceed 0.5 rem. Other scientific groups, including the International Commission on Radiation Protection, have also stressed the need to keep radiation doses to unborn children as low as practicable.

All Nuclear Regulatory Cornnii&sion li'ensees are now required* to inform all Individuals who work in a

  • By Title 10. Part 19 of the Code of Federai Regulations.

restricted area of the health protection problems asso- ciated with radiation exposure. This instruction would in many cases include information on the possible risks to unborn babies. The regulations also state*

that licensees should keep radiation exposures as low as practicable. According to the National Council on Radiation Protection and Measurements, particular efforts should be made to keep the radiation exposure of an embryo or fetus at the very lowest practicable level during the entire period of pregnancy.

Thus it is the responsibility of your employer to take all practicable steps to reduce your radiation exposure. Then it is your responsibility to decide whether the exposure you are receiving is sufficiently low to protect your unborn child. The advice of your employer's health physicist or radiation protection officer should be obtained to determine whether radia- tion levels in your working areas are high enough that a baby could receive 0.5 rem or more before birth. If so, the alternatives that you might want to consider are:

(a) If you are now pregnant or expect to be soon, you could decide not to accept or continue assignments in these areas.

(b) You could reduce your exposure, where possible, by decreasing the amount of time you spend in the radiation area, increasing your distance from the radiation source, and using shielding.

(c) If you do become pregnant, you could ask your employer to reassign you to areas involving less exposure to radiation. If this is not possible, you might consider leaving your job. If you decide to take such steps, do so without delay. The unborn child is most sensitive to radiation during the first three months of your preg.

nancy.

(d) You could delay having children until you are no longer working in an area where the radiation dose to your unborn baby could exceed 0.5 rem.

"In Title 10, Part 20.

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You may also, of course, choose to:

(e) Continue working in the higher radiation areas, but with full awareness that you are doing so at some small increased risk for your unborn child.

The following facts should be noted to help you make a decision:

1. The first three months of pregnancy are the most important, so you should make your decision quickly.

2.

At the present occupational exposure limit, the actual risk to the unborn baby is small, but experts disagree on the exact amount of risk.

3.

There is no need to be concerned about sterility or loss of your ability to bear children. The radiation dose required to produce such effects is more than 100

times larger than the Nuclear Regulatory Commission's dose limits for adults.

4.

Even if you work in an area where you receive only 0.5 rem per three-month period, in nine months you could receive 1.5 reins, which exceeds the full-term limit suggested by the NCRP. Therefore, if you d&cide to restrict your unborn baby's exposure as recommended by the NCRP, be aware that the 0.5 rem limit applies to

the full nine-month pregnancy.

The remainder of this document contains a brief explanation of radiation and its effects on humans. As you will see, some radiation is present everywhere and the levels of radiation most employees of Nuclear Regulatory Commission licensees receive are not much larger than these natural levels. Because the radiation levels in the facility where you will be working are required by law to be kept quite low, there is not considered to be a significant health risk to individual adult employees.

0.072 rem per year. The average dose from one chest X-ray is 0.045 rem.

Radiation can also be received from natural sources such as rock or brick structures, front consumer pro- ducts such as television and glow-in-the-dark watches, and from air travel. The possible annual dose from working 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> a day near a granite wall at the Redcap Stand in Grand Central Station, New York City, is 0.2 rem, and the average annual dose in the United States from TV, consumer products, and air travel is 0.0026 rem.

Radiation, like many things, can be harmful. A large dose to the whole body (such as 600 reins in one day)

would probably cause death in about 30 days, but such large doses result only from rare accidents. Control of exposure to radiation is based on the assumption that any exposure, no matter how small, involves some risk.

The occupational exposure limits are set so low, how- ever, that medical evidence gathered over the past 50

years indicates no clinically observable injuries to indi- viduals due to radiation exposures when the established radiation limits are not exceeded. This was true even for exposures received under the early occupational ex- posure limits, which were many times higher than the present limits. Thus the risk to individuals at the occupational exposure levels is considered to be very low. However, it is impossible to say that the risk is zero.

To decrease the risk still further, licensees are expected to keep actual exposures as far below the limits as practicable.

The current exposure limits for people working with radiation have been developed and carefully reviewed by nationally and internationally recognized groups of scientists. It must be remembered, however, that these limits are for adults. Special consideration is appropriate when the person being exposed is, or may be, an expectant mother, because the exposure of an unborn child may also be involved.

Prenatal Irradiation The prediction that an unborn child would be more sensitive to radiation than an adult is supported by observations for relatively large doses.

Large doses delivered before birth alter both physical development and behavior in experimentally exposed animals. A

report of the National Academy of Sciences states that short-term doses in the range of 10 to 20 reins cause subtle changes In the nerve cells of unborn and infant rats. The report also states, however, that no radiation- induced changes in development have been demon- strated to result In experimental animals from doses up to about I rem per day extended over a large part of the period before birth.

The National Academy of Sciences also noted that doses of 25 to 50 reins to a pregnant human may cause Discussion of Radiation The amount of radiation a person receives is called the "dose"

and is measured in "reins." The average peron in the United States gets a dose of one rem from natural sources every 12 years. The dose from natural radiation is higher in some states, such as Colorado, Wyoming, and South Dakota, primarily because of cosmic. radiation. There the average person gets one rem every 8 years.

Natural background radiation levels are also much higher in certain local areas. A dose of one rem may be received in some areas on the beach at Guarapari, Brazil, in only about 9 days, and some people in Kerala, India, get a dose of one rem every 5 months.

Many people receive additional radiation for medical reasons. The annual radiation dose averaged over the United States population from diagnostic X.rays is

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growth disturbances in her offspring. Such doses sub.

stantially exceed. of course, the maximum permissible occupational exposure limits.

Concern about prenatal exposure (i.e., exposure of a child while in its mother's uterus) at the permissible occupational levels is primarily based on the possibility that cancer (especially leukemia) may develop during the first 10 years of the child's life. Several studies have been performed to evaluate this risk. One study involved the followup of 77.000 children exposed to radiation before birth (because of diagnostic abdominal X-rays made for medical purposes during their mother's pregnancy).

Another stud)y involved the followup of 20.000 such children.

In addition,

1292 children who received prenatal exposure during the bombing of Hiroshima and Nagasaki were studied. Although contradictory results have been obtained, most of the evidence sugests a relationship between prenatal exposure and an increased risk of childhood cancer.

Summary Occupational exposures to radiation arc being kept low. flowever, qualified scientists have recommended that the radiation dose to a pregn,,.nt woman should not exceed 0.5 rem because of possible risks to her unborn child. Since this 0.5 rem is lower than the dose generally permitted to adult workers, women may want to take special actions to avoid receiving higher exposures, just as they might stop smoking during pregnancy or might climb stairs more carefully to reduce possible risks to their unborn children.

Bibliography Donald G. Pizzarello and Richard L. Witcofski, Basic Radiation Biology, Philadelphia: Lea and Febizer. 1967.

2.

National Academy of Sciences - National Research Council, The Effccts on Populations of Exposure to Low Levels of Ioni:ing Radiation, Washington, D.C., November 1972.

3.

National Council on Radiation Protection and Measurements. Basic Radiation Protection Criteria, NCRP Report No. 39, Washington, D.C., January

15, 1971.

4.

United Nations. Ionizing Radiation: Levels and Effects, 2 vol., Reports of the United Nations Scientific Committee on the Effects of Atomic Radiation, Report No. A/8725, United Nations.

New York, 1972.

5.

US. Atomic Energy Commission, Division of Technical Information, Understanding the Atom Series:

Atoms, Nature and Alan The Genetic Effects of Radiation The Natural Radiation Environment Your Body and Radiation UNITED STATES

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