Any woman who has given birth knows that shedding baby weight can be a long and arduous process. Now scientists are finding that women who start off with a body mass index (BMI) of 30 or higher—technically obese—are at a huge disadvantage. According to the new study, slated to appear in next month’s issue of Obstetrics & Gynecology, obese moms-to-be who gain more than 15 pounds during pregnancy are much more likely to retain the weight a year after giving birth. Fifteen pounds you say? Give a girl a break! Indeed, the Institute of Medicine says obese women should limit their baby bump to between 11 and 20 pounds. Considering that nearly 50 percent of women in the United States begin their 9-month journey either overweight or obese—double the number from a mere 20 years ago—the study’s implications are considerable.Backed by funding from the Centers for Disease Control and Prevention, scientists examined the medical records of 1,656 obese women in Oregon and Washington, all members of Kaiser Permanente Northwest, and found that nearly 75 percent of them packed on more than 15 pounds while they were expecting and 21 percent gained 35 pounds or more. That’s problematic because obese women are more likely to have pregnancy-related complications, such as gestational diabetes, gestational hypertension, and preeclampsia, says Dr. Victor J. Stevens, the study co-author and a senior investigator at the Kaiser Permanente Center for Health Research. What’s even more discouraging is that one year after giving birth, the average participant was still schlepping 40 percent of her baby weight. “We are trying to turn the obesity epidemic around,” says Stevens, “but when a woman gains 40 or 50 pounds during pregnancy and keeps much of it on, we are headed in the wrong direction.”