As part of pre-conception planning, I received a rubella vaccination two months ago. At the time, my husband and I were advised to wait three months before trying to conceive. However, I’ve read that studies have shown that the vaccine has never been known to harm an unborn baby. Exactly how great is the risk?
Rubella (German measles) is a mild viral illness that occurred in epidemics prior to the licensure of the rubella vaccine in 1969. Congenital rubella syndrome (CRS) – a group of serious birth defects first described in 1941 by Australian ophthalmologist Dr. Norman Gregg – results from rubella infection of a pregnant woman, particularly during the first trimester of pregnancy. While fetal infection may occur throughout pregnancy, birth defects are rare when infection occurs after the 20th week of pregnancy.
Pregnancy remains a contraindication to rubella vaccination (reason not to give the vaccine), because we know that rubella virus can harm the fetus. Nevertheless, some women have received the vaccine while pregnant, because their pregnancy may not have been known at the time of vaccination.
The Centers for Disease Control and Prevention (CDC) maintained a registry of such women from 1979-1989, to determine whether CRS would occur in the infants of these mothers. No cases of CRS occurred in the infants born to the 321 women who were entered into the registry. Nevertheless, because the population of women followed up in the registry included only a fraction of pregnant women who received the vaccine, the theoretical risk (a statistical concept) is 1.7%.
Although the risk is indeed small and only theoretical, you need to decide for yourselves, how much risk, if any, you are willing to take on.
