Seasonal influenza vaccination may halve stillbirth risk

Women who receive a seasonal influenza vaccination during pregnancy may have over 50 per cent less risk of experiencing a stillbirth than unvaccinated mothers, according to a new study.
Researchers from Western Australia Department of Health analysed data from nearly 60,000 births that occurred during the southern hemisphere's 2012 and 2013 seasonal influenza epidemics.
The retrospective study used midwives' records to examine a cohort of 58,008 births - 52,932 to mothers who had not received the vaccine and 5,076 to mothers who had been vaccinated during pregnancy.
All births took place in Western Australia between April 2012 and December 2013. The adjusted risk of stillbirth among vaccinated mothers was 51 per cent lower than the risk among women who had not been vaccinated, researchers said.

They also found that stillbirth rates increased after periods of influenza virus circulation and decreased during the months prior to the influenza season, although the seasonal differences were not statistically significant.
The study's results are consistent with those of a 2000 study in Switzerland that recorded increased incidence of stillbirth in relation to the northern hemisphere's influenza season, as well as with similar research conducted during the influenza A/H1N1 pandemic, researchers said.

"Our results are particularly exciting since they show we can get the same protection during seasonal epidemics, which occur every winter," said Annette Regan from the Western Australia Department of Health.

"Unfortunately, we know that about 40 per cent of pregnant women go unvaccinated, missing out on these benefits. I am hoping results like these can convince more pregnant women to get vaccinated each year," Regan said.
The findings were published in the journal Clinical Infectious Diseases.