By now, most women know that cigarettes and alcohol don't mix with pregnancy. But supersize portions and second helpings may also be off the table for many women, thanks to yesterday's announcement by a research group that influences clinical guidelines for obstetricians across the country. In a report titled "Weight Gain in Pregnancy: Reexamining the Guidelines," the Institute of Medicine (IOM) is advising moms-to-be to be more mindful of weight gain—not just after conception, but before it.
According to the new guidelines, women entering pregnancy at a normal weight should gain 25 to 35 pounds; underweight women, 28 to 40 pounds; overweight women, 15 to 25 pounds; and obese women, 11 to 20 pounds. These targets aren't dramatically different from those in the IOM's previous study, published in 1990, with the exception of new limits for obese women, who had been advised to gain at least 15 pounds. But beneath the data charts, the report conveys a subtle but powerful new message: From the moment you decide you're ready to have a baby, you and your doctor need to talk much more openly, and seriously, about weight. "To improve maternal- and child-health outcomes, women not only should be within a normal BMI range when they conceive but also should gain within the ranges recommended in the new guidelines," reads the report brief. "Meeting these challenges means that women will need preconception counseling, which may include plans for weight loss; and both women and their care providers need to know and understand the new guidelines. For many women, this will mean gaining less weight, which may be particularly challenging for women who are overweight or obese at conception."
What happened to the cozy old adage of eating for two—one that was alive and well two decades ago, when the IOM published a report that clearly focused on the problems of gaining too little. "That was an era when more women were drinking and smoking, which destroy nutrients that mothers pass on to their babies," explains Jacques Moritz, M.D., director of gynecology at St. Luke's–Roosevelt Hospital in New York City. Women were also nearly as likely to enter pregnancy too lean (22 percent) as overweight (24 percent). These trends coincided with an epidemic of low birth weight, which is associated with a variety of developmental problems. "The thought was that gaining enough weight was the most important thing," says Marjorie Greenfield, M.D., associate professor of reproductive biology at Case School of Medicine and University Hospitals of Cleveland.
But as times have changed, so have our proportions. Currently, more than 40 percent of women of childbearing age are overweight and nearly 20 percent are obese. Moreover, while just 12 percent of women are underweight, more than 25 percent of all women are gaining more than 40 pounds per pregnancy. "Now, we're faced with two problems: too many women are overweight heading into pregnancy, and too many are gaining excess during it," says Dr. Greenfield. Both scenarios put women at a higher risk for developing gestational diabetes and preeclampsia, delivering via cesarean section, and having macrosomic (extralarge) infants. Big babies—think nine pounds and over—are more prone to birth injuries (from shoulder dislocations to brain damage) and, according to recent studies, weight problems later in life. Overweight moms, meanwhile, are at greater risk for health issues like heart disease and certain cancers down the road. "It's becoming clear that there are more complications associated with being too heavy than too thin during pregnancy," says Dr. Greenfield.
