From the Guidelines
Pregnant women should not receive the MMR (measles, mumps, rubella) vaccine due to the theoretical risk it poses to the developing fetus, particularly the rubella component which could potentially cause congenital rubella syndrome if given during pregnancy. This recommendation is based on the precautionary principle, as no cases of congenital rubella syndrome have been documented from vaccine administration, but the theoretical risk outweighs the benefit during pregnancy since these infections can usually be delayed until after delivery 1.
Key Considerations
- The MMR vaccine is a live attenuated vaccine, and its administration during pregnancy is contraindicated due to the potential risk to the fetus 1.
- If a woman is planning pregnancy, she should receive the MMR vaccine at least one month before conception if she is not already immune.
- For pregnant women who are exposed to measles or mumps, immune globulin may be recommended instead.
- After delivery, women with no evidence of immunity should receive the MMR vaccine before hospital discharge.
- The standard MMR dose is 0.5 mL administered subcutaneously, typically given as two doses separated by at least 28 days.
Counseling and Pregnancy Testing
- Women of childbearing age should be asked if they are pregnant or intend to become pregnant in the next 4 weeks before administering the MMR vaccine 1.
- Routine pregnancy testing of women of childbearing age before administering a live-virus vaccine is not recommended 1.
- If a pregnant woman is inadvertently vaccinated or if she becomes pregnant within 4 weeks after MMR vaccination, she should be counseled regarding the theoretical basis of concern for the fetus; however, MMR vaccination during pregnancy should not ordinarily be a reason to terminate pregnancy 1.
From the Research
Vaccination During Pregnancy
- The MMR vaccine is a live and/or live-attenuated virus vaccine, which is generally contraindicated during pregnancy due to a theoretical risk to the fetus 2, 3.
- According to the Advisory Committee on Immunization Practices (ACIP), live attenuated vaccines, including MMR, are contraindicated during pregnancy 4.
- The American College of Obstetricians and Gynecologists (ACOG) recommends that pregnant women receive inactivated virus, bacterial vaccines, or toxoids, but does not mention the MMR vaccine as a recommended vaccine during pregnancy 5, 6.
- It is recommended that women who are or will be pregnant during influenza season receive an annual influenza vaccine, and all pregnant women should receive a tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine during each pregnancy 5, 6.
MMR Vaccine Specifics
- The MMR vaccine is not recommended for pregnant women, and women who have inadvertently received the vaccine during pregnancy should not be counseled to terminate the pregnancy due to a teratogenic risk 2.
- Non-pregnant women immunized with a live or live-attenuated vaccine, including MMR, should be counseled to delay pregnancy for at least four weeks 2.
- Women who are breastfeeding can still be immunized with live or killed vaccines, including MMR 2.