Take This Shot While Pregnant

Flu shot in pregnant women reduces potential birth complications

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) What's worse than morning sickness? How about having the flu while pregnant too? But getting your flu shot while pregnant might do more good than just preventing this miserable outcome.

A recent study has found that flu vaccinations may also help protect mothers from a variety of other birth complications.

"Get your flu shot while pregnant."

Lead author Deshayne Fell, an epidemiologist for a study group in Ontario, Canada, and colleagues investigated the impact of being vaccinated for influenza on birth outcomes.

The researchers pulled data from a birth record database called BORN in Ontario. They looked at 55,570 children born during the H1N1 flu pandemic, excluding any multiples such as twins or triplets from the study.

During this period, from November 2009 to April 2010, 42 percent of the women were vaccinated for the H1N1 strain of influenza. They found that women who received the flu vaccination experienced lower rates of stillbirth, preemies and underweight babies.

The researchers adjusted their calculations to account for various characteristics, such as whether the mother smoked, her educational level and her income.

The women who received their flu shots were 34 percent less likely to give birth to a stillborn child and were 28 percent less likely to have a preterm baby, delivered before the 32nd week of pregnancy.

"This is one of the only studies large enough to evaluate the association between maternal flu vaccination and stillbirth—a very rare event," Fell said.

Flu-vaccinated women were also 19 percent less likely to have a child who was in the bottom third percentile for the week of pregnancy when they were born (their gestational age).

The researchers also looked at possible side effects or adverse events in the women during the weeks before and after they gave birth, but the vaccinated women did not have any higher rate of negative outcomes than the unvaccinated women.

"Pregnant women are generally very, very careful about what they put into their bodies," said co-author Mark Walker, a Senior Scientist at the Ottawa Hospital Research Institute. "Such a large-scale study that shows no adverse perinatal outcomes resulting from the H1N1 flu vaccine will be extremely helpful when discussing maternal vaccination."

The study appeared online May 22 in the American Journal of Public Health. The research was funded by the Canadian Institutes of Health Research.

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Review Date: 
May 23, 2012
Last Updated:
October 8, 2012