There's no consensus on how much weight an overweight or obese woman should gain during pregnancy. In 2009, the Institute of Medicine changed its guidelines, lowering it to 11 to 20 pounds for obese moms-to-be, but not everyone agrees. A study finds that there may be few differences in pregnancy-related results for women who gain more or less weight.

The study, published in the December issue of the journal Obesity, looks at data on 691 obese women. Of those, 57.7 percent had a prepregnancy body mass index of 30 to 34.9 (level I obesity) and the rest had a BMI of 35 or greater.

Among those women, about half gained 25-35 pounds during pregnancy and the others gained 11-20 pounds.

Average infant birth weight was about the same in both groups and no differences were seen in numbers of low birthweight infants or admissions to neonatal ICUs. Women who gained 11-20 pounds had slightly fewer cesarean deliveries compared to those who gained more. There was a minor difference between the groups in how many women developed preg-nancy-related high blood pressure.

The authors wrote that the results suggest that obese pregnant women may be able to safely gain the amount of weight recommended by the Institute of Medicine.