Flu shot cuts preterm births

Most women are careful about what drugs they take or what treatments they have while they are pregnant, but the H1N1 swine flu shot given during pregnancy seems to have an added bonus: a lower risk of stillbirths or premature births, and a lower number of very small babies born. These unexpected results were published by a team of Canadian researchers in the American Journal of Public Health and support the use of the vaccine in pregnant women, who tend to catch the bug more easily and get more ill.

The team looked at 55,570 single-child births during the 2009-10 H1N1 pandemic born to women who did or did not get their flu shot, using data from Ontario's birth record database, BORN. The women who had been vaccinated--42% of the whole group--were around a third less likely to have a stillborn baby, just under a third less likely to give birth before 32 weeks, and a fifth less likely to have a very small baby. There were no increased levels of side effects for vaccinated mothers and babies around birth.

"These are all significant results, but especially interesting is the finding that the vaccinated mothers were one-third less likely to have a stillborn child," says lead author Deshayne Fell, an epidemiologist for BORN Ontario. "This is one of the only studies large enough to evaluate the association between maternal flu vaccination and stillbirth—a very rare event."

"The most important thing about this study was that the flu vaccine did no harm to the fetus," Dr. Mark Walker, an obstetrician at the Ottawa Hospital and the study's co-author, told the Vancouver Sun. "Not only was the vaccine safe; there was a potential benefit."

The researchers will continue to watch these children, to see if the vaccinations have any long-term effects.

- read the press release
- see the article in the Vancouver Sun
- check out the abstract