Ivanhoe Newswires)-- Immunization of pregnant women may help increase unborn babies birth weights, and give them a healthier start at life.
A recent study used a randomized trial consisting of 340 healthy pregnant women in Bangladesh in their third trimester. Researchers looked at the effect of vaccinating with the influenza vaccine on babies born to vaccinated mothers. It was part of the Mother's Gift project looking at the safety and efficacy of pneumococcal and influenza vaccines in pregnant women in Bangladesh. The participants were divided into two groups, one with 170 women who received the influenza vaccine, and the second who received the pneumococcal vaccine as a control. Researchers compared the weight of babies born in two periods, one in which there was circulation of an influenza virus and one with limited circulation.
Babies that are small for their gestational age have an increased risk of health issues over the course of their lives.
The researchers discovered that there were fewer babies who were small for their gestational age born to mothers in the flu vaccine group when the virus was circulating, with 25.9% who were small compared with 44.8% in the control group. When the virus was dormant, the ratio of small-for-gestational-age births was similar in both groups. During the period with circulating influenza virus, the average birth weight was 3178 g in the flu vaccine group and 7% higher than 2978 g in the control group. The rate of premature births was also reduced in the influenza vaccine group.
"We found that immunization against influenza during pregnancy had a substantial effect on mean birth weight and the proportion of infants who were small for gestational age," writes Dr. Mark Steinhoff, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, with coauthors.
"Our data suggest that the prevention of infection with seasonal influenza in pregnant women by vaccination can influence fetal growth," the authors stated.
The researchers measured that 10 maternal influenza vaccinations given year-round prevented one small-for-gestational-age birth, dropping to 6 vaccinations during the period in which the influenza virus was circulating.
The study was conducted by a team of US and Bangladeshi researchers from the Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Johns Hopkins University, Baltimore, Maryland; Emory University, Atlanta, Georgia; the International Centre for Diarrheal Disease Research, Dhaka, Bangladesh; and the Centers for Disease Control and Prevention, Atlanta, Georgia.
The authors concluded that if further research supports their findings, adding an influenza vaccine to routine vaccination programs during pregnancy could help children have a better start.
SOURCE: Canadian Medical Association Journal, February 21, 2012