Your Weight Gain During Pregnancy Can Predict The Gender of Your BabyKatlyn Joy |26, December 2014
According to a study published in the December issue of PLOS ONE, when women have a lower gestational weight gain they are more likely to have baby girls.
Researcher Kristen Navaro of the University of Georgia's College of Agricultural and Environmental Sciences looked at data from the Centers for Disease Control and Prevention, which involved over 46 million births covering a 23 year period.
It is a known fact that male babies are more susceptible to adverse conditions in utero than female babies. Boys are more likely to be born prematurely and are more often miscarried as well. Navaro began her research looking to find out whether the ratio of male to female babies were skewed according to weight gained during pregnancy.
"Fetuses are differentially susceptible to inadequate weight gain during pregnancy and that puts males more at risk at least at certain points of gestation," said Navaro.
Generally, 105 boys are born to 100 girls, worldwide. However, in times of extreme difficulties, such as famine or war, the rate of girls born increases.
The research uncovered that when women gain 20 or fewer pounds in pregnancy, the birth rate of girls overtakes boys, 52 to 48.
Male and female embryos grow at different rates. Males have higher numbers of cell divisions at the beginning of life, and also higher metabolic rates. They grow at a more rapid rate until the third trimester, when it appears things even out between boys and girls.
Therefore, male embryos require more energy than females in the first months of gestation. It was found that women carrying boys needed 10 percent higher intake of energy.
Women who are known to have lower caloric intakes, such as those with conditions such as anemia, bulimia, or celiac disease give birth to fewer boys. On the other hand, women likely to have higher caloric intakes, such as those who binge eat or are wealthy, produce more boys.
Also, women who had low body mass index or BMIs prior to pregnancy had fewer male children.
Navaro believes this research may be used for further study to determine whether weight recommendations should be altered depending on the gender of the child being carried.
"Currently, the recommendations for weight gain in pregnancy are the same whether the fetus is male or female, even though it is well known that they grow at different rates and have different metabolic rates. I think it is important to continue the research to determine whether women carrying boys should actually be eating more than women carrying girls in order to maximize the chances of the fetus's survival."
While Navaro works in the poultry science department as a reproductive endocrinologist. However, she doesn't think that precludes her research from having impact across species. She studies reproductive systems of several species and believes that cross-referencing the effects and mechanisms within them can be helpful overall.
Studies in cows and mice have both shown a link between lower level nutritional intake and a decrease in male offspring.
Navaro also looked at data specifically among the four identified races of white, black, Asian, and American Indian. While the rate of male births between races varies noticeably, with 50.2 percent male among American Indians, 50.9 in Asians, 50.5 in both blacks and whites, the rates had similar impact with weight gain factored in.
What This Means for You
It's too soon to know if separate weight chart or recommendations will be issued someday for moms carrying boys versus girls, but some insight can be gained for the present. Paying attention to the recommended weight gain according to BMI and sticking close is important according to several studies looking at gestational weight gain and impact on births and later health in offspring.
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