Among pregnant women who did not develop gestational diabetes, overweight women were 65 percent more likely, and obese women 163 percent more likely, to have overly large babies than their healthy weight counterparts. In this study, an overly large infant was identified based on having a birth weight over the 90th percentile for their gestational age at delivery and gender. Gaining excess weight during pregnancy also contributed to having a large for gestational age baby, regardless of maternal weight or whether she developed gestational diabetes.
This Kaiser Permanente study of nearly 10,000 pregnant women from Kaiser Permanente Southern California examined adverse outcomes among women with and without gestational diabetes as defined by the recently established International Association of Diabetes and Pregnancy Study Groups guidelines. Overly large babies are at increased risk for birth complications and for being overweight or obese later in life.
"Unhealthy pre-pregnancy body weight, gestational diabetes and excess weight gain during pregnancy are all contributors to problems during pregnancy and at delivery," said study lead author Mary Helen Black, PhD, of Kaiser Permanente Southern California's Department of Research & Evaluation. "It's possible that a large percentage of these problems may be prevented by helping overweight or obese women lose weight before they become pregnant or control their weight gain during pregnancy. Future intervention studies are needed to substantiate this."
Researchers examined the electronic health records of 9,835 women who received prenatal care and delivered their babies at the Kaiser Permanente Southern California Downey Medical Center (formerly called Bellflower Medical Center) over a five-year period from October 30, 2005 to December 31, 2010. Sixty percent of these women were overweight or obese and 19 percent developed gestational diabetes.
"By losing weight to achieve a healthy weight before pregnancy and by keeping their weight gain during pregnancy within guidelines established by the Institute of Medicine, women may decrease the health risks to their unborn babies and themselves," said study co-author David A. Sacks, MD, adjunct investigator at the Department of Research & Evaluation and a retired obstetrician-gynecologist from the Kaiser Permanente Downey Medical Center. "For children of overweight and obese women, the risks include an increased likelihood of having an excessive amount of body fat and being overweight or obese themselves, which can lead to high blood pressure, heart disease and type 2 diabetes later in life."
This study is part of ongoing efforts at Kaiser Permanente to conduct studies and increase public awareness of the prevalence and effects of obesity in the United States. Earlier this year, Kaiser Permanente partnered with HBO (Home Box Office), the Institute of Medicine, the National Institutes of Health, the Centers for Disease Control and Prevention and the Michael & Susan Dell Foundation to launch one of the most ambitious public education campaigns addressing America's obesity epidemic to date, including the documentary series The Weight of the Nation on HBO.
Kaiser Permanente's broader efforts to understand, prevent and treat adverse pregnancy outcomes. Previous Kaiser Permanente research includes:
- A study of over 11,000 women with gestational diabetes found that referral to a telephone-based nurse management program was associated with lower risk of high baby birth weight and increased postpartum glucose testing (American Journal of Obstetrics and Gynecology, 2012).
- A recent study that found a woman's risk of developing diabetes during pregnancy can be identified up to seven years before she becomes pregnant based on routinely assessed measures of blood sugar and body weight (American Journal of Obstetrics and Gynecology, 2011).
- A study that found cardio-metabolic risk factors such as high blood sugar and insulin, and low high-density lipoprotein cholesterol that are present before pregnancy, predict whether a woman will develop diabetes during a future pregnancy (American Journal of Epidemiology, 2010).
- A study of 10,000 mother-child pairs that showed treating gestational diabetes during pregnancy can break the link between gestational diabetes and childhood obesity (Diabetes Care, 2007).
- An earlier study of 1,145 pregnant women that found that women who gain excessive weight during pregnancy, especially in the first trimester, may increase their risk of developing diabetes later in their pregnancy (Obstetrics and Gynecology, 2010).