In 2009 The Institute of Medicine (IOM) updated their guidelines for how much weight women should gain during pregnancy for optimal outcomes for them and their and babies. These guidelines are endorsed by the American College of Obstetricians and Gynecologists. The June 6 issue of the Journal of the American Medical Association has a report of an analysis of 1.3 million pregnancies from 23 studies to see how well those IOM guidelines work. (1) Bottom line they work ok. Pregnant mothers who gain less or more than these guidelines have more problems with their babies. Mothers who gained too little had a higher risk of delivering babies that were too little or premature. Mothers who gained too much had a higher risk of babies who were too big. Maternal risk of diabetes during pregnancy could not be adequately determined but did not show a strong signal either way. C-sections were more common in mothers who gained too much.
So how much should you gain during pregnancy. These guidelines are too complicated. Normal weight mothers should gain about 30 lbs during pregnancy but underweight mothers should gain more and overweight mothers should gain less. Weight class is defined by body mass index (BMI). Maybe a better rule would be to say everybody should gain 30 lbs. Small mothers would gain more proportional to their weight and big mothers would gain less. In general there is a lot less variation in the size of newborn babies than there is in the size of adult people and that is what we’re trying for.
The big question that cannot be answered by watching a million pregnant women and see what happens is whether trying to change weight gain during pregnancy is possible or makes any difference. In an editorial in this issue of JAMA, Dr Caughey from the Ob-Gyn Department of Oregon Health & Science University mentions evidence that it is hard to change the weight gain of women much during pregnancy and it makes even less difference in outcomes of their babies. But then he talks at length about better ways to try and make pregnant women gain less weight during pregnancy. (2)
Poor women. The terrible terribly complicated complication of pregnancy can really throw a wrench into fighting for a beautiful body. Women should really be making more money than men for doing the same work.
Better bottom line – try to stay active during pregnancy and eat whatever your body tells you to eat.
John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- firstname.lastname@example.org or phone-354-6605.