Saturday, July 6, 2002
Mom's Early Weight Gain Found Key in Newborn Size
July 05, 2002 02:14 PM ET Email this article Printer friendly version By Amy Norton
NEW YORK (Reuters Health) - A woman's weight gain during pregnancy is well known to influence her newborn's birth weight, but new research suggests that pounds gained during the first trimester may be particularly important.
The study, which followed 389 women from before pregnancy to delivery, found that the weight moms-to-be put on in the first 3 months of pregnancy was more important than later weight gain in influencing their newborns' birth weight.
This stands in contrast to past research, which has generally found that weight gain in the second and third trimesters is what really counts, according to the authors of the new study.
But unlike past studies, this one measured women's weight before they got pregnant, rather than relying on participants' recall of their pre-pregnancy weight, lead author Judith E. Brown told Reuters Health.
Brown and her colleagues at the University of Minnesota in Minneapolis report the findings in the July issue of the American Journal of Clinical Nutrition.
The researchers found that, overall, for every kilogram (2.2 pounds) a woman gained in the first trimester, there was a 31-gram boost in infant birth weight. There was a similar, though not as strong, relationship between second trimester weight gain and birth weight. In contrast, third trimester weight gain was not found to influence birth weight.
Brown speculated that a woman's early weight gain may influence the "trajectory" of fetal growth--meaning the fetal growth pattern may be set in a way that cannot be changed much by late-pregnancy weight gain.
However, the "ideal" amount of weight a woman should put on in the first trimester is unclear.
"We haven't had prospective research results to determine with any confidence what weight gain in the first trimester of pregnancy should be," Brown said.
However, she and her colleagues note in their report, if the current findings are confirmed in other studies, it could change certain views on prenatal nutrition.
For example, they write, the "window of opportunity" for enhancing fetal growth could be quite small if there were a delay in a woman's prenatal care or entry into nutrition programs like the federal Supplemental Food and Nutrition Program for Women, Infants and Children--commonly known as WIC.
SOURCE: American Journal of Clinical Nutrition 2002;76:205-209.