New Data Confirms Tdap in Pregnancy Is Safe

November 28, 2014

The resurgence of whooping cough has put the Tdap vaccine front and center. Since the vaccine is safe, newborns-via antibodies from mom-can be protected.

If there remained doubt, new research indicates what was already presumed: Tdap administered during pregnancy is safe.

With the resurgence of whooping cough, public health officials and physicians have been touting the Tdap vaccine for all pregnant women. But there remained limited data on the safety of administering the vaccine to pregnant women.

Pertinent Points:

- A review of birth data in California showed that the Tdap vaccine is safe to administer to pregnant women.

- The vaccine did not increase the risk of preterm birth, small for gestational age,
or hypertensive disorders of pregnancy.

Researchers, reviewing data from 123,494 singleton pregnancies in California, found that the vaccine did not increase the risk of preterm birth or small for gestational age. In addition, there was no increased risk of hypertensive disorders of pregnancy.

The analysis did pinpoint a small but statistically significant increased risk of a diagnosis of chorioamnionitis among women who received the vaccine. Still, the authors noted that the chorioamnionitis results should be interpreted with caution because the magnitude of the risk was small.

Among all pregnancies, the rate of small-for-gestational-age infants was nearly identical for those who received the vaccine and for those who did not. And when researchers looked at the important safety marker of preterm delivery, they found that those who received the Tdap fared better than those who were unexposed, with 6.3% delivering early among the Tdap-exposed population compared with 7.8% in the unexposed group.

Among the study population, which included births from two California datasets between January 2010 and November 2012, just 21% of women received Tdap.

The findings provide more information supporting the recommendations already in place-pregnant women should receive a Tdap vaccine between 27 and 36 weeks' gestation.

The findings are published in JAMA.