Pregnant women are recommended to receive a single dose of pertussis-containing vaccine in each pregnancy
dTpa vaccine is recommended as a single dose in each pregnancy.
See Table. Recommendations for vaccines that are routinely recommended in pregnancy: inactivated vaccines in Vaccination for women who are planning pregnancy, pregnant or breastfeeding for more details.
Vaccination during pregnancy reduces the risk of pertussis in young infants by 90%.17,18 This results from direct passive protection by transplacental transfer of pertussis antibodies from the mother to the fetus during pregnancy.
Vaccination is recommended with each pregnancy, including pregnancies that are closely spaced, to provide maximal protection to every infant. This is because:
- vaccine-induced pertussis antibody levels wane over time
- the antibody level needed in mothers to pass on immunity to newborn infants is unknown
The optimal time for pertussis vaccination in pregnancy is between mid 2nd trimester and early 3rd trimester (between 20 and 32 weeks gestation). This is because:
- levels of pertussis antibodies that are likely to be protective are detected in infants born to mothers vaccinated in the 2nd and 3rd trimesters
- maternal antibodies are actively transported to the fetus from 13 weeks,20 with maximum transfer 30 weeks gestation onwards21
- pertussis antibody levels do not peak until about 2 weeks after vaccination19
Pregnant women typically have a routine morphology scan by ultrasound at around 20 weeks gestation and present to a maternity care provider in relation to this scan. Providers may use the 20 week scan as a prompt to provide pertussis vaccine or schedule a vaccination visit. There are no safety concerns if a pregnant woman receives pertussis vaccine before 20 weeks gestation.
If pregnant women are not vaccinated between 20 and 32 weeks, they should receive pertussis-containing vaccine as soon as possible and at any time up to delivery. If given within 2 weeks of delivery, the newborn may not be adequately protected.22
If pregnant women receive the vaccine earlier than 20 weeks, they do not need a repeat dose during the same pregnancy. Evidence shows transfer of pertussis antibodies to the infant in women who received dTpa vaccine as early as 13 weeks gestation.22