Tdap Vaccination Safety During Pregnancy Studied

Elyse O. Kharbanda MD MPH HealthPartners Medical and Dental Interview
Elyse O. Kharbanda MD MPH
HealthPartners Medical and Dental Group

Medical Research: What is the background for this study? What are the main findings?

Dr. Kharbanda: In 2010, due to a pertussis outbreak and neonatal deaths, the California Department of Public Health recommended that the Tdap vaccine be administered during pregnancy.  Tdap is now recommended by the Advisory Committee on Immunization Practices (ACIP) for all pregnant women during each pregnancy.  We wanted to assess the impact of this recommendation.

The main findings were that Tdap vaccination during pregnancy was not associated with increased risk for hypertensive disorders of pregnancy, preterm birth, or having a baby who is small for his or her gestational age.

The study found a small increased risk for being diagnosed with chorioamnionitis, an inflammation of the fetal membranes caused by bacterial infection.  These findings should be interpreted with caution as the magnitude of the risk was small.  In addition, there was no associated risk for preterm birth, which often occurs as a result of chorioamnionitis.  Furthermore, among the subset of women with a chorioamnionitis diagnosis whose charts were reviewed, many did not have a clinical picture that was clearly consistent with chorioamnionitis.

Medical Research: What should clinicians and patients take away from your report?

Dr. Kharbanda: This study provides important information on the safety of Tdap vaccination during pregnancy. It is particularly significant because there is limited prior safety data, along with continued widespread pertussis transmission.  In addition it provides validation for the  current recommendations to routinely vaccinate during pregnancy.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Kharbanda: This study describes the safety of Tdap vaccination in women not previously vaccinated.  As current ACIP recommendations are that women receive Tdap during every pregnancy, continued monitoring of repeated Tdap doses during subsequent pregnancies will be important.