A study shows that among women who received the tetanus, diphtheria, and acellular pertussis (Tdap) vaccine during pregnancy, there was no increased risk of adverse events in the mothers or adverse birth outcomes in newborns for women who received a tetanus-containing vaccine in the previous 5 years. A news release from The JAMA Network notes safety data on repeated Tdap vaccination in pregnancy has been lacking, according to background information in the article.

Lakshmi Sukumaran, MD, MPH, of the Centers for Disease Control and Prevention, and colleagues conducted a study that included 29,155 pregnant women aged 14 through 49 years. Data from 2007 to 2013 was used from 7 Vaccine Safety Datalink sites in Colorado, Minnesota, Oregon, California, Wisconsin, and Washington. The researchers examined outcomes for women who received Tdap during pregnancy following a prior tetanus-containing vaccine less than 2 years before, 2 to 5 years before, and more than 5 years before.

The research team found no notable differences in rates of acute adverse events in the mothers (fever, allergy, and local reactions) or adverse birth outcomes in neonates (small for gestational age, preterm delivery, and low birth weight) when comparing women who were vaccinated with Tdap during pregnancy regardless of the length of time since a prior tetanus-containing vaccine, according to The JAMA Network news release.

The researchers explain that future research is needed to determine if there are differences in other important adverse pregnancy outcomes, such as stillbirth, when Tdap is given in pregnancy in close intervals from prior tetanus-containing vaccines, as indicated on The JAMA Network news release.

The authors of the study write, “Our findings should reassure patients and clinicians who might be hesitant to give Tdap vaccine to pregnant women who recently received a Tdap or other tetanus-containing vaccination.”

Source: The JAMA Network