It has been nearly two decades since guidelines for how much weight a woman should gain during pregnancy were issued by the Institute of Medicine. In that time, more research has been conducted on the effects of weight gain in pregnancy on the health of both mother and baby. There have also been dramatic changes in the population of women having babies. American women are now a more diverse group; they are having more twin and triplet pregnancies, and they tend to be older when they become pregnant. Women today are also heavier; a greater percentage of them are entering pregnancy overweight or obese, and many are gaining too much weight during pregnancy. Many of these changes carry the added burden of chronic disease, which can put the mother and her baby's health at risk.
Given these changes, the IOM's 2009 report Weight Gain During Pregnancy: Reexamining the
Guidelines examines weight gain during pregnancy from the perspective that factors that affect pregnancy begin before conception and continue through the first year after delivery.
The new weight gain guidelines are based on revised Body Mass Index (BMI) categories and now have a recommendation for obese women. To meet the recommendations of the report, women need to gain within the weight gain ranges for their BMI category. Achieving the recommended gain will require individualized attention and support from a woman's care providers as well as her family and community.