The risk vaccines pose to pregnant women is one of many safety topics in which popular opinion differs from scientific evidence. Multiple studies have found no evidence of harm, but surveys show people are unsure. The case in favor of vaccines became stronger still this week.
Research in the journal Obstetrics and Gynecology found 74,000 pregnant women who received a flu shot, in any trimester, were no more likely to experience pregnancy complications. Rates of severe morning sickness, urinary tract infections, high blood pressure and other complications in the 2010-11 flu season were compared. The researchers looked at incidence of these problems 42 days after vaccination and through to the birth.
"This is the single largest and best and most reliable safety study we have to date. We didn't have concerns about [the safety of the vaccine], and this puts the icing on the cake," Vanderbilt University Medical School chair Dr. William Schaffner told Reuters. The finding has strengthened convictions that the benefits of receiving the flu vaccine outweigh the risks. Catching the flu during pregnancy increases the risk of death, respiratory disease requiring hospitalization and premature labor and delivery.
Flu vaccines cut the risk of these events, while also preparing babies for the first months outside the womb. Previous studies have shown the vaccine's protection passes across the placenta to give babies some defenses against the virus. The protection can help shield babies from flu in their first 6 months, at which point childhood vaccination programs begin. Schaffner said this favorable risk-reward ratio means "there should be no hesitation for women getting the vaccine."