NFID Annual Conference on Vaccinology Research

NFID Annual Conference on Vaccinology Research

April 17, 2015
2 min read

Tdap appears safe for pregnant women, infants

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BETHESDA, Md. — Preliminary study results suggest pregnant women who received the tetanus-diphtheria-acellular pertussis vaccine were not at increased risk for adverse maternal or birth outcomes.

In 2012, the CDC’s Advisory Committee on Immunization Practices recommended that all women, regardless of vaccination status, receive the Tdap vaccine during pregnancy. According to the ACIP, pregnant women should receive the vaccine between 27 and 36 weeks gestation, which has been identified as the optimal time to maximize the transfer of antibodies from mother to child.

According to Abbey B. Berenson, MD, PhD, professor of obstetrics and gynecology and pediatrics at the University of Texas Medical Branch, there have been few studies on Tdap vaccination during pregnancy since the ACIP made its recommendation.

Abbey B. Berenson

Berenson and colleagues assessed the frequency and safety of Tdap vaccination during pregnancy, comparing maternal and infant outcomes among pregnant women who did and did not receive the vaccine. The study included 885 women aged 27 years or younger from Galveston County, Texas, who delivered a singleton infant at the University of Texas Medical Branch between November 2012 and June 2014. Of these women, 61.9% agreed to receive Tdap vaccination during pregnancy. According to Berenson, the population was ethnically diverse and tended to be poor, with over 90% having annual family incomes of less than $30,000.

The researchers conducted a retrospective review of electronic medical records to compare outcomes and examine variables related to pregnancy and delivery.

Results indicated that women who received Tdap were significantly more likely to be employed and less likely to be smokers.

“We also found that women who received the Tdap vaccine during pregnancy had a slightly higher mean number of prenatal visits, although their entry into health care did not differ,” Berenson said during her presentation. “And, as might be expected, those who received the Tdap vaccine also were more likely to receive the flu vaccine during their pregnancy.”

An examination of maternal outcomes showed no differences between groups in pregnancy-induced hypertension, chorioamnionitis, preterm labor, preterm delivery, preterm premature rupture of membranes, postpartum hemorrhage or oligohydramnios.

Additionally, after adjusting for confounders, Berenson and colleagues found no differences in outcomes related to labor and delivery or to the infant’s health.

Berenson noted that the study was focused on a single county in Texas, and the limited age of the women may not be representative of the general population. The researchers currently are conducting a larger study that is not limited by age to produce more generalizable results.

“Tdap vaccination has been well accepted in this population,” Berenson said. “We also found that women who received the Tdap vaccination during pregnancy had somewhat healthier pregnancies.” – by John Schoen

Berenson A, et al. Abstract S17. Presented at: Annual Conference on Vaccine Research; April 13-15, 2015; Bethesda, Maryland.

Disclosure: Berenson reports no relevant financial disclosures.