a) Except as otherwise provided in
subsections (d) and (e) of this Section, the licensee or registrant shall
ensure that the dose equivalent to an embryo/fetus during the entire pregnancy,
due to occupational exposure of a declared pregnant woman, does not exceed 5
mSv (0.5 rem). (For recordkeeping requirements, see Section
340.1160(d)
of this Part.)
b) The dose
equivalent to an embryo/fetus shall be taken as the sum of:
1) The deep dose equivalent to the declared
pregnant woman during the entire pregnancy; and
2) The dose equivalent to the embryo/fetus
from radionuclides in the embryo/fetus and radionuclides in the declared
pregnant woman during the entire pregnancy.
c) The licensee or registrant shall make
efforts to avoid substantial variation above a uniform monthly exposure rate to
a declared pregnant woman so as to satisfy the limit in subsection (a) of this
Section.
AGENCY NOTE: The National Council on Radiation Protection and
Measurements report entitled "Recommendations on Limits for Exposure to
Ionizing Radiation", NCRP 91, published June 1, 1987, recommends that no more
than 0.5 mSv (0.05 rem) of the allowed dose to the embryo/fetus be received
during any one month during a declared pregnancy.
d) If the declared pregnant woman has not
notified the licensee or registrant of the estimated date of conception, the
licensee or registrant shall ensure that the dose equivalent to an
embryo/fetus, as specified in subsection (b) of this Section, due to
occupational exposure of the declared pregnant woman does not exceed 0.5 mSv
(0.05 rem) per month, during the remainder of the pregnancy. If after initially
declaring her pregnancy, a declared pregnant woman advises the licensee or
registrant of the estimated date of conception, the dose limits specified in
subsections (a) and (e) of this Section shall apply.
AGENCY NOTE: The Agency encourages licensees and registrants
to explain to declared pregnant workers that providing an estimated date of
conception will enable the licensee or registrant to more accurately assess the
radiation dose equivalent to the embryo/fetus and assist the licensee or
registrant in determining appropriate precautions to be taken for the remainder
of the pregnancy.
e) If by
the time the woman informs the licensee or registrant of the estimated date of
conception the dose equivalent to the embryo/fetus has exceeded
4.5 mSv (0.45 rem), the
licensee or registrant shall be deemed to be in compliance with subsection (a)
of this Section if the additional dose equivalent to the embryo/fetus as
specified in subsection (b) of this Section does not exceed 0.5 mSv (0.05 rem)
during the remainder of the pregnancy.
