Women who are extremely obese may not need to gain that much weight during pregnancy, and those who don't add too many pounds may find themselves and their babies healthier.
The findings were presented recently at the Society for Maternal-Fetal Medicine's annual meeting in San Francisco. The study looked at data on 73,977 women from New York's Finger Lakes region who gave birth to one child between 2004 and 2008.
Among the women, 4% were underweight, 48% were normal weight, 24% were overweight, and 24% were obese. In the obese category, 13% were class one (having a BMI of 30 to 34.99), 6% were class two (a BMI of 35 to 39.99) and 5% were class 3 (a BMI of 40 or above).
Gaining less weight than recommended during the second and third trimester for women who fell under class 2 or 3 obesity was not linked with having a baby considered small for its gestational age or with poor outcomes for mothers. However, gaining less weight than recommended during the second and third trimester for women in other weight categories was associated with having a smaller baby.