••• Chapter 63^ Reproductive Toxicology^633
❍ Does radiation from diagnostic studies present a risk to pregnant women?
Aside from the emotional distress induced by this exposure, probably not. The risk of teratogenesis with
exposures of <5 rads is minuscule. The following table presents radiation doses presented to the uterus by various
radiographic procedures.
Study View Dose/Study (mrad)
Chest AP and lateral 0.05
Abdomen AP and lateral 125
IVP 1000
Upper GI series 50
Barium enema 2000–4000
CT abdomen 2500❍ Pregnant patient in her second trimester presents to the emergency room with acute abdominal pain. She is
refusing any imaging studies and asks about the risks of radiation. How would you counsel her?
The potential risks of in utero radiation exposure of a developing fetus include prenatal death, IUGR, small
head size, mental retardation, organ malformation, and childhood cancer. The risk of each effect depends on the
gestational age at the time of exposure, fetal cellular repair mechanisms, and the absorbed radiation dose level.
However, in general from typical radiologic examinations the fetal risks are minimal and, therefore, that radiologic
and nuclear medicine examinations that may provide significant diagnostic information should not be withheld
from pregnant women.
❍ What immunizations are contraindicated during pregnancy?
In general, live virus vaccines are contraindicated during pregnancy. These include measles, mumps, rubella,
varicella, and yellow fever. However, all toxoids, immunoglobulins, and killed virus vaccines are considered safe in
pregnancy and should not be withheld, if indicated.
❍ What is the current recommendation for giving influenza vaccine to pregnant women?
The influenza vaccine is an inactivated live vaccine and so far no risks from immunization have been described.
According to the current ACOG guidelines, all women who are pregnant in the second and third trimester during
the flu season (October-March) and women at high risk of pulmonary complications regardless of the trimester
should receive the influenza vaccination.
❍ Is breastfeeding a contraindication to immunization?
Breastfeeding is not a contraindication to immunizations. Live and inactivated vaccines and toxoids can all be
given during this time.
❍ What are the hazardous effects of rubella vaccination during embryogenesis?
Even though the vaccine contains live attenuated virus, there are no known cases of congenital rubella syndrome
(malformations of the heart and CNS, deafness, cataracts, mental retardation) as a consequence of inadvertent
vaccination during early pregnancy. However, to be safe, all women receiving the vaccine should be advised to
postpone pregnancy for 3 months.