Excessive Weight Gain During Pregnancy Poses Health Risks

The health risks associated with weight gain are well known, but when you are pregnant it takes on a whole new significance. While it’s true that you are “eating for two,” eating twice as much usually results in excessive weight gain, meaning you will have more difficulty losing the weight after the baby is born. It also means an increased risk of having a large baby. According to a new study, gaining 40 pounds or more during pregnancy almost doubles the risk of having a baby that weighs 9 pounds or more, posing health risks to both mother and child. Bigger babies can mean riskier births, including vaginal tearing and bleeding, and often the need for a Caesarean section. For the baby there is a risk of getting stuck in the birth canal, often leading to broken collar bones. Heavier babies are also prone to obesity and type 2 diabetes later in life, the study authors said.

For the study, researchers at the Kaiser Permanente Center for Health Research in Portland, Oregon looked at 41,540 pregnant women who gave birth to singleton babies in Hawaii, Oregon and Washington from 1995 through 2003. Patient medical records and birth certificates were used to determine the mother’s weight and the baby’s birth weight. All mothers-to-be also underwent glucose screening for gestational diabetes, which is a known risk factor for having a heavier baby. More than 20 percent of those who gained more than 40 pounds gave birth to large babies, compared to less than 12 percent of those who gained less than 40 pounds. Of those who both gained more than 40 pounds and suffered gestational diabetes, 29.3 percent had big babies, while the odds for women with normal glucose levels and who gained less than 40 pounds were only 9.3 percent. “More than one in five women gain too much weight during pregnancy and only 5 percent have gestational diabetes,” said the study’s lead author Teresa Hillier, M.D., an endocrinologist and senior investigator at the Kaiser Center.

The study concludes that women should be careful about their weight during pregnancy. Current guidelines issued by the federal Institute of Medicine in 1990, which are now being re-evaluated, advise that an underweight mother (BMI below 19.8) gain 28 to 40 pounds; women with normal weight (BMI of 19.8 to 26.0) gain 25 to 35 pounds; and overweight women (BMI above 26) gain 15 to 25 pounds during pregnancy. But, surprisingly, a third of the women surveyed in an unrelated study said they received no advice about gestational weight gain from their health care providers. “Providers should do a better job about counseling,” Dr. Hillier said. “They need to pay attention to weight, and focus on healthy weight gain.”

But Hillier also cautioned, “Not gaining enough (weight during pregnancy) is a risk for the baby as well. The focus should be eating healthfully: low-fat dairy, protein, lots of fruit and vegetables, also, under the guidance of a physician, getting moderate amounts of exercise.”

The study was published in the November issue of Obstetrics and Gynecology.