Jabbing Pregnant Women

H1N1 influenza vaccination given to pregnant women linked to better outcomes for babies

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) When the H1N1 influenza blew through in the flu season of 2009-2010, some worried about an additional flu vaccine to get. Pregnant mothers who got jabbed may have helped their babies.

A recent large-scale study reveals that infants born to mothers who elected to get vaccinated against the H1N1 influenza were more likely to turn out healthy, on time and at an appropriate weight.

"Get the flu vaccine while pregnant."

Deshayne Fell, MSc, of the Perinatal Epidemiology Research Unit at the IWK Health Centre in England, led a study that looked at how well babies did that were born to mothers who received the H1N1 flu vaccine during the 2009-2010 season.

Fell and colleagues used a database in Ontario, Canada where they had access to the records of 55,570 mothers who gave birth to a single child.

About 42 percent of these women (a total of 23,340) had received the H1N1 influenza vaccination while they were pregnant.

The results showed that women who received the vaccine were slightly less likely to give birth to underweight babies and were almost half as likely (58 percent as likely compared to unvaccinated mothers) to give birth early to a preemie.

Mothers were about 66 percent less likely to have a child die if they had received the H1N1 vaccine.

Certain characteristics of the mothers were taken into account for possibly affecting the outcomes, including the mother's age, her insurance status, her history of having preemies and whether she smoked while pregnant

The researchers also considered whether mothers had a number of chronic health conditions, including asthma, high blood pressure, diabetes or heart issues.

Finally, they also took into account any birth complications or conditions the mothers had, including pre-eclampsia, gestational diabetes, placenta previa, hemorrhaging, umbilical cord problems or similar delivery-related issues.

The researchers concluded that the H1N1 vaccination was linked to better outcomes for the babies during the time the H1N1 virus was circulating.

"We found that pregnant women who received an H1N1 vaccination were less likely to have a very preterm infant, a small-for-gestational-age infant or a fetal death, even after consideration of important confounding factors," the authors wrote.

This does not, however, mean that the vaccine caused the better outcomes, and the authors acknowledged that their study needs to be confirmed in future studies that are designed to better assess the effectiveness of the vaccine.

There are other possible characteristics of the mothers that may have influenced the results but which the researchers did not have knowledge or access to, such as the quality of prenatal care received.

The study was published online April 19 in the American Journal of Public Health. The research was funded by the Canadian Institutes of Health Research and the Public Health Agency of Canada. No conflicts of interest were noted.

Reviewed by: 
Review Date: 
April 25, 2012
Last Updated:
October 8, 2012