Office of Human Resources Management - Safety and Health Management Division

Radiation Safety Staff
 

Technical Bulletin

Declared Pregnant Woman

The Nuclear Regulatory Commission's (NRC) Standards for Protection Against Radiation (10 CFR Part 20) require that the dose to an embryo/fetus during the entire pregnancy, due to occupational exposure of a declared pregnant woman, does not exceed 0.5 rem (5 mSv). This dose is ten times lower than the occupational dose allowed for a radiation worker. This document describes how to implement a program that satisfies this safety requirement.

Date:  9/6/96 

John T. Jensen /S/
Director, Radiation Safety Staff

- the embryo/fetus is monitored for radiation exposure during the pregnancy; and

- the radiation dose is within the regulatory limits.

Federal safety regulations are gender neutral and it is inappropriate for facility management to arbitrarily place additional restrictions on a woman who appears to be pregnant. 

By training, women who become pregnant should be aware of the additional safety precautions available to them to assure a low radiation exposure during the gestation period. However, they may be satisfied with their current work situation, and believe that existing precautions and procedures provide an adequate measure of safety during their pregnancy. It is for this reason that the program is voluntary.

Attendance records, indicating the date of training, and the individuals trained (including their signature) must be maintained by the facility.

- is known to have given birth;

- informs the facility that she is no longer pregnant; or

- informs the facility that she no longer wants to be considered a declared pregnant woman.

Twelve months after the declaration is submitted, the declaration will expire.

Any agreed to changes, or an acknowledgment that no changes are necessary, should be written and signed by all parties.

Typically, these declarations are placed in the individual's official personnel file, along with a signed statement from the declared pregnant woman that she has received additional training (such as a review of the Frequently Asked Questions) and consultation regarding her work situation. The LRPO, Permit Holder, supervisor, personnel officer, or other appropriate individual should also sign any other consulting or training documentation.

For example, studies of the effects of radiation on animals and humans demonstrate clearly and conclusively that large doses of radiation - such as 100 rems (1 sievert) - cause serious developmental defects in many of the body's organs when the radiation is delivered during the period of rapid organ development (References 2, 3, 4, and 5).
 

The developing human brain has been shown to be especially sensitive to radiation. Mental retardation has been observed in the survivors of the atomic bombings in Japan exposed in utero during sensitive periods.

(Continued)

The sensitivity of the brain undoubtedly reflects its structural complexity and its long developmental period (and hence long sensitive period). The most sensitive period is during about the 8th to 15th weeks of gestation followed by a substantially less sensitive period for the two months after the 15th week (Reference 4). There is no known effect on the child's developing brain during the first two months of pregnancy or the last three months of pregnancy (Reference 4).

No developmental effects caused by radiation have been observed in human groups at doses at or below the 5-rem (50-millisievert) occupational dose limit. Scientists are uncertain whether there are developmental effects at doses below 5 rems (50 millisieverts). It may be that the effects are present but are too mild to measure because of the normal variability from one person to the next and because the tools to measure the effects are not sensitive enough. Or, it may be that there is some threshold dose below which there are no developmental effects whatsoever.

In view of the possibility of developmental effects, even if very mild, at doses below 5 rems (50 millisieverts), scientific advisory groups consider it prudent to limit the dose to the embryo/fetus to 0.5 rem (5 millisieverts) (References 1 and 2). At doses greater than 5 rems (50 millisieverts), such as might be received during an accident or during emergency response activities, the possibility of developmental effects increases.

While the evidence for increased sensitivity of the embryo/fetus to cancer induction from radiation exposure is inconclusive, it is prudent to assume that there is some increased sensitivity. Scientific advisory groups assume that radiation exposure before birth may be 2 or 3 times more likely to cause cancer over a person's lifetime than the same amount of radiation received as an adult (Reference 1). If this is true, there would be 1 radiation-induced cancer death in 200 people exposed in utero at the occupational dose limit of 5 rems (50 millisieverts) (Reference 1). Scientific advisory groups have considered this risk to be too high and have thus recommended that the radiation dose to the embryo/fetus be limited to a maximum of 0.5 rem (5 millisieverts). At that dose, there would be 1 radiation-induced cancer death per 2000 people. This would be in addition to the 400 cancer deaths from all causes that one would normally expect in a group of 2000 people.

Of particular concern is excessive consumption of alcohol during pregnancy. The U.S. Public Health Service has concluded that heavy alcohol consumption during pregnancy (three drinks per day and above) is the leading known cause of mental retardation (Reference 6). Children whose mothers drank heavily during pregnancy may exhibit developmental problems such as hyperactivity, distractibility, short attention spans, language difficulties, and delayed maturation, even when their intelligence is normal.
 

In studies tracking the development of children born to light or moderate drinkers, researchers have also correlated their mothers' drinking patterns during pregnancy with low birth weight, decreased attention spans, delayed reaction times, and lower IQ scores at age four years. Youngsters whose mothers averaged three drinks per day during pregnancy were likely to have IQs averaging five points lower than normal.
 

Cigarette smoking may also harm the unborn (Reference 6). There is a direct correlation between the amount of smoking during pregnancy and the frequency of spontaneous abortion and fetal death. Children of mothers who smoke while pregnant are more likely to have impaired intellectual and physical growth. Maternal smoking has also been associated with such behavioral problems in offspring as lack of self-control, irritability, hyperactivity, and disinterest. Long-term studies indicate that these children perform less well than matched youngsters of nonsmokers on tests of cognitive, psychomotor, language, and general academic functioning.
 

Alcohol and smoking are only examples of other risks in pregnancy. Many other toxic agents and drugs also present risk. In addition, many factors that cannot be controlled present risk. There is an increased risk in pregnancy with increasing maternal age. Maternal disease may be an important risk factor. Malnutrition, toxemia, and congenital rubella may be associated with birth defects. Maternal diabetes and high blood pressure have been associated with problems in the newborn. In addition, many birth defects and developmental problems occur without an obvious cause and without any obvious risk factors. For example, viruses that we may not even be aware of can cause defects, and defects can arise from spontaneous random errors in cell reproduction. But these are things that we can't do anything about.
 

In summary, you are advised to keep radiation exposure of your unborn child below 0.5 rem, but you should also remember that alcohol consumption, cigarette smoking, and the use of other drugs can do a great deal of harm.

It is most likely that your employer will tell you that you can continue to perform your job with no changes and still meet the NRC's limit for exposure to declared pregnant women. No USDA employees have received, in nine months, occupational radiation doses that are above the 0.5-rem (5-millisievert) limit for a declared pregnant woman.
 

If the dose you currently receive is above the 0.5-rem (5-millisievert) dose allowed for a declared pregnant woman, it is quite likely that your employer can and will make a reasonable accommodation that will allow you to continue performing your current job, for example, by having another qualified employee perform a small part of the job that accounts for much of the radiation exposure.
 

On the other hand, it is possible, although not common, that your employer will conclude that there is no reasonable accommodation that can be made without undue hardship that would allow you to do your job and remain within the dose limits for a declared pregnant woman. In these few instances, your employer may conclude that you can no longer be permitted to do your current job, that you must be removed from your job, and that there is no other job available for someone with your training and job skills.
 

If your employer concludes that you must be removed from your current job in order to comply with the lower dose limits for declared pregnant women, you may be concerned about what will happen to you and your job. The answer to that depends on your particular situation. That is why you should talk to your employer about your particular situation. In addition, telephone numbers that may be useful for obtaining information are listed in the Sources of Additional Information. 

If you have a miscarriage and become pregnant again before you have revoked your original declaration of pregnancy, you should submit a new declaration of pregnancy because the date of conception has changed.

(1) your employer knows you have given birth, 

(2) you inform your employer that you are no longer pregnant, or 

(3) you inform your employer that you no longer wish to be considered pregnant.

The general principles for maintaining exposure to radiation as low as reasonably achievable are summarized below. You should already be applying these principles to your job, but now is a good time to review them.

1. Wear lab coats or other protective clothing if there is a possibility of spills.

2. Use gloves while handling unencapsulated radioactive materials.

3. Wash hands after working with unencapsulated radioactive materials.

4. Do not eat, drink, smoke, or apply cosmetics in areas with unencapsulated radioactive material.

5. Do not pipette radioactive solutions by mouth.

Region I (800) 432-1156; 

Region II (800) 577-8510; 

Region III (800) 522-3025; and 

Region IV (800) 952-9677. 
 

These regions are described on NRC Form-3 "Notice to Employees", which should be posted at your workplace.
 

Legal questions should be directed to the Regional Counsel, and technical questions should be directed to the Division of Radiation Safety and Safeguards.

For individuals with hearing impairments, the EEOC's TDD number is (800) 800-3302.

USDA Radiation Safety Staff 
5601 Sunnyside Avenue
Mail Stop 5510
Beltsville, MD  20705-5000

Phone: (301) 734-4945
Fax: (301) 734-5050