Flu Vaccines for Moms Increase Birth Weights of Their Children

Tuesday, May 04, 2010

Continuing its ground-breaking work on the effects of flu vaccines, a research team from Cincinnati Children’s Hospital Medical Center has discovered that birth weights increase for babies of women who are immunized for the flu.

The work of Mark C. Steinhoff, M.D., director of the Center for Global Child Health, is being presented at 1 p.m ET Tuesday, May 4, at the Pediatric Academic Societies meeting in Vancouver, Canada.

“What makes these findings important,” Dr. Steinhoff explains, “is that for the first time, we have proven that beyond protecting moms and their babies from influenza, the flu vaccine also increases the birth weight of the infants, giving them a better chance at a healthier life.”

This study is part of the Mother’s Gift project which took place in Bangladesh under Dr. Steinhoff’s oversight. Part of the Mother’s Gift findings were published in the New England Journal of Medicine in 2008 and showed that influenza vaccine not only prevents pregnant women from getting influenza but also protects their infants. It was the first study to demonstrate that the inactivated influenza vaccine provides such dual protection.

The new data is further evidence of the effect of the flu vaccine, which is recommended for pregnant women in the United States, but is not licensed for infants younger than 6 months of age.

The birth weight work was part of the prospective, blinded, randomized Mother’s Gift trial carried out from August 2004 to November 2005 involving 340 pregnant urban Bangladeshi women. The study considered time intervals of high and low flu virus circulation and found when there was no flu circulation there were similar birth weights among both the control group and the vaccinated group.

However, during the interval of flu circulation, when the flu vaccine prevented illness, the mean birth weight of infants in the influenza vaccine group was 7 percent greater, and the proportion of “small for gestation age” babies was more than halved from 41 percent in the control group to 17 percent in the flu vaccine group.

“More study is needed to confirm these data, but this clearly suggests that prevention of influenza in pregnancy improves fetal growth,” Dr. Steinhoff said.

In addition to the Center for Global Child Health at Cincinnati Children’s, others participating in the work included the International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh; the Rollins School of Public Health, Emory University, Atlanta; and the Centers for Disease Control and Prevention, Atlanta.

About Cincinnati Children’s

Cincinnati Children’s Hospital Medical Center is one of 10 children’s hospitals named to the Honor Roll in U.S. News and World Report’s 2009-10 America’s Best Children’s Hospitals. It is ranked #1 for digestive disorders and highly ranked for its expertise in respiratory diseases, cancer, neonatal care, heart care, neurosurgery, diabetes, orthopedics, kidney disorders and urology. Cincinnati Children’s is one of the top two recipients of pediatric research grants from the National Institutes of Health (NIH). Internationally recognized for quality and innovation by The Joint Commission, the Institute for Healthcare Improvement and the federal Agency for Healthcare Research and Quality, it has collaborations with hospitals and health systems around the world. . Additional information can be found at

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Thomas McCormally