Live Attenuated Vaccines Should Be Avoided in Pregnancy
Live attenuated vaccines are contraindicated during pregnancy due to the theoretical risk of placental transmission and fetal infection, whereas immune globulins, killed (inactivated) vaccines, and toxoids are considered safe. 1, 2, 3
Why Live Attenuated Vaccines Are Contraindicated
Live attenuated vaccines contain weakened but replicating organisms that pose a theoretical risk of crossing the placenta and causing fetal viremia or bacteremia. 1, 3
Specific live attenuated vaccines that must be avoided during pregnancy include:
Safe Vaccine Categories During Pregnancy
Immune globulins are safe and can be administered during pregnancy without restriction, as they contain pre-formed antibodies and pose no risk of infection. 1
Killed (inactivated) vaccines are considered safe throughout pregnancy because they contain non-replicating organisms that cannot cause infection:
- Inactivated influenza vaccine (strongly recommended for all pregnant women) 4, 5
- Hepatitis A (inactivated) 1, 2
- Hepatitis B 1, 4, 2
- Polio (inactivated/IPV) 1
- Cholera (inactivated) 1
- Pneumococcal vaccines 2
- Meningococcal vaccines 1, 2
Toxoids are safe during pregnancy as they contain inactivated bacterial toxins:
- Tetanus toxoid 1, 3
- Tdap (tetanus, diphtheria, acellular pertussis) - routinely recommended at 27-36 weeks in every pregnancy 4, 5, 3
Important Clinical Caveats
Women who inadvertently receive live vaccines during pregnancy should NOT be counseled to terminate the pregnancy based on teratogenic risk, as actual documented harm is rare and no adverse birth outcomes have been consistently reported. 1, 6
Women who receive live vaccines should be counseled to delay pregnancy for at least 4 weeks after vaccination. 6
Women susceptible to rubella or varicella should receive these vaccines immediately after delivery, ideally before hospital discharge. 2, 3
Common Pitfalls to Avoid
Do not confuse live attenuated influenza vaccine (LAIV/nasal spray) with inactivated influenza vaccine - the former is contraindicated while the latter is strongly recommended during pregnancy. 4, 2
Do not withhold inactivated vaccines or toxoids from pregnant women due to unfounded safety concerns - these are explicitly safe and often beneficial. 1, 2
Do not assume all vaccines are contraindicated in pregnancy - only live attenuated vaccines carry this restriction. 3, 6