Who: Most women
When: At your first prenatal visit (generally six to ten weeks into your pregnancy)
How: A blood test
Why: To detect antibodies to rubella (German measles), which indicate immunity to the disease. You likely received the MMR vaccine at some point in your life, but immunity may have worn off, so ideally this is something doctors like to check for during a preconception visit. That way, if you’re not immune, you can be vaccinated (and should wait three months following vaccination to conceive). If antibodies are not present in a pregnant woman, exposure to the disease could cause birth defects, blindness, deafness, preterm birth, miscarriage or stillbirth, among other problems.
Results and follow-up: The vast majority of women in the U.S. are immune, thanks to a major vaccination effort, but if you’re not, you should make sure that your kids, if you have any others at home, have had all of their shots and that anyone else at home who’s not immune gets vaccinated. If there’s even a single known case of rubella in your community, you should stay home until it’s confirmed that the danger of infection has passed. Sounds drastic, but if you contract rubella during the first 12 weeks, there’s up to an 85 percent chance that your baby will develop congenital rubella syndrome (CRS), which can cause deafness, eye defects, and major neurologic problems. After 20 weeks of pregnancy, thankfully, there’s little risk that a rubella infection would cause any birth defects.