All pregnant women are advised to get the Tdap vaccine, which protects against tetanus, diphtheria, and pertussis, also known as whooping cough.
In a double-blind, placebo-controlled clinical trial, researchers randomized 33 pregnant women to a vaccination at 30 to 32 weeks gestation, and 15 to a placebo shot.
The researchers found no serious side effects in any of the women or infants, and there were no cases of pertussis in either group. But women in the vaccination group had high concentrations of pertussis antibodies, and so did their newborn babies. That did not substantially affect the babies' response to the recommended four doses of the infant version of the vaccine given from age 2 months to 13 months.
"We have shown that by receiving the Tdap during gestation, the babies get high concentrations of pertussis antibodies," said Dr. Flor M. Munoz of Baylor College of Medicine, the lead author of the JAMA article. "This is likely to be protective during the first two months, before they are able to get their own vaccinations."