Vaccines Recommended for Third Trimester Baby Arrival Preparation
All pregnant women should receive Tdap vaccine between 27 and 36 weeks of gestation during each pregnancy, and influenza vaccine can be administered at any time during pregnancy. 1
Tdap Vaccine (Tetanus, Diphtheria, and Pertussis)
Timing and Administration
- Administer Tdap between 27 and 36 weeks gestation, with earlier administration within this window (27-30 weeks) appearing to produce higher antibody concentrations in cord blood. 1, 2
- This timing is critical because:
- A minimum of 2 weeks is required to mount maximal immune response to vaccine antigens 1, 2
- Active transport of maternal immunoglobulin G does not substantially occur before 30 weeks of gestation 1, 2
- Maternal antibodies wane quickly—women vaccinated in first or second trimester have low antibody levels at term 1, 2
Effectiveness and Safety
- Maternal Tdap vaccination during 27-36 weeks gestation is 80-91% effective at preventing infant pertussis and 85% more effective than postpartum vaccination. 1, 3
- Among infants infected with pertussis, maternal vaccination was 58% effective in preventing hospitalization 1
- Experience with tetanus-toxoid containing vaccines suggests no excess risk for severe adverse events when receiving Tdap with every pregnancy 1
- The potential benefit of preventing pertussis morbidity and mortality in infants outweighs theoretical concerns of adverse events 1
Critical Points
- Tdap must be administered during EACH pregnancy, regardless of prior vaccination history. 1, 4
- If Tdap is not given during pregnancy and the woman has never received it, administer immediately postpartum 1
- Tdap may be given simultaneously with influenza vaccine 1
Influenza Vaccine
Timing and Administration
- Inactivated influenza vaccine is recommended for all pregnant women in any trimester of pregnancy. 5, 6
- Can be administered at any gestational age during flu season 4
- If not given during pregnancy, should be offered postpartum (up to 6 months post-birth) 4
Rationale
- Primarily protects the mother, who is at increased risk for serious influenza complications during pregnancy 6
- Growing evidence shows infants benefit from passive antibody protection against influenza complications 6
Special Situations Requiring Immediate Tdap
Wound Management
- If ≥5 years have elapsed since last tetanus booster and wound management is needed, administer Tdap immediately regardless of gestational age. 1, 2, 7
- Do not delay for optimal timing windows when wound prophylaxis is indicated 7
Incomplete or Unknown Tetanus Vaccination History
- Women who have never been vaccinated against tetanus require a 3-dose primary series: first dose immediately, second dose at 4 weeks, third dose at 6-12 months. 1, 7
- Tdap should replace one dose of Td, preferably between 27-36 weeks gestation 1, 7
- The urgency stems from preventing maternal and neonatal tetanus, which carries significant morbidity and mortality risk 7
Tetanus Booster Due
- If >10 years since previous Td booster, administer Tdap between 27-36 weeks gestation 1
Common Pitfalls to Avoid
- Do not miss the optimal 27-36 week window for Tdap administration 2
- Do not skip Tdap during pregnancy even if the woman received it recently outside of pregnancy—each pregnancy requires Tdap 1, 2
- Do not delay the first dose in unvaccinated pregnant women waiting for the "optimal" trimester—start immediately 7
- Do not assume vaccination history is complete without documentation; treat uncertain histories as unvaccinated 7
- Do not delay Tdap when indicated for wound management during pregnancy 2, 7
Close Contact Vaccination ("Cocooning")
- Adolescents and adults who have or anticipate close contact with an infant <12 months (parents, siblings, grandparents, childcare providers, healthcare personnel) should receive a single dose of Tdap if not previously vaccinated 1
- Ideally, these persons should receive Tdap at least 2 weeks prior to contact with the infant 1