Flu Vaccine Decreases Risk of Premature or Low-Birth-Weight Babies
- By BSTQ Staff
Pregnant women who are vaccinated against the flu are significantly less likely to deliver premature or low-birth-weight babies compared with unvaccinated expectant mothers, according to a Canadian study. In the study, researchers looked at all women who delivered an infant at any hospital in the province of Nova Scotia during the two flu seasons immediately following the 2009 H1N1 pandemic. The researchers found that, overall, the odds of preterm birth (defined as deliveries at less than 37 weeks’ gestation) and lower-birth-weight infants were lower among the babies of vaccinated women. “Both Canadian and World Health Organization guidelines now recommend routine seasonal influenza vaccination of all pregnant women in any trimester,” said the study’s first author, Alexandra Legge, a fourth-year medical student at Dalhousie University in Halifax.
Based on more than 12,000 women in Nova Scotia who gave birth in the immediate aftermath of the H1N1 flu pandemic, the study adds to mounting evidence that the flu can have detrimental effects for both mothers and their babies. As women get closer to their due dates, their immune systems change, making them more vulnerable to serious illness from flu and other infections, which can put stress on the fetus. An earlier study from Nova Scotia showed that pregnant women who are admitted to the hospital with respiratory illnesses during flu season are more likely to deliver babies that are small for their gestational age or have a low birth weight. However, of the 12,233 women who gave birth to a live-born or stillborn infant between November 2010 and March 2012, only 16 percent received the flu vaccine during their pregnancy, the researchers said. And, while vaccination rates in pregnancy increased during H1N1 (government data suggest that 64 percent of pregnant women in Nova Scotia received the H1N1 vaccine during the pandemic), experts worry that it hasn’t translated into higher rates of flu vaccination since.
