More than one-third of women of reproductive age in the United States are considered overweight or obese. Tipping the scales before pregnancy increases a woman’s risk of developing gestational diabetes, which, in turn, increases the risk of maternal and fetal complications and type 2 diabetes after pregnancy.
Minority women in particular are at greater risk for gestational diabetes because of genetic background (susceptibility or family history), and in addition to entering pregnancy heavier, they often gain more weight than their white counterparts.
The preliminary results of a new study at Grady Memorial Hospital suggest a lifestyle intervention implemented in the early stages of pregnancy in this high-risk population could prevent excessive gestational weight gain and reverse this dangerous trend.
“We know lifestyle interventions promoting healthy diets and physical activity are effective in improving insulin sensitivity and in reducing the risk of developing type 2 diabetes,” says Guillermo E. Umpierrez, MD, professor of medicine in the Division of Endocrinology at Emory University School of Medicine, and chief of diabetes and endocrinology at Grady Memorial Hospital. “But whether the same effort would improve response to pregnancy-induced insulin resistance has been unclear.”
To determine what effect lifestyle interventions would have among women at high risk for gestational diabetes, Umpierrez and his team conducted a pilot study among a group of minority pregnant women receiving prenatal care at Grady Memorial Hospital from April 2010 to September 2012. All women were considered overweight or obese, and randomly assigned to receive either a lifestyle intervention during their monthly prenatal care visits or regular care as provided by their obstetrician.
A total of 28 participants were randomized to receive the intervention focused on eating more fruits and vegetables, limiting unhealthy sugar and fats and increasing moderate physical activity. A group of 29 participants received regular care and limited education regarding weight control and healthy eating and physical activity during pregnancy.
“Pregnancy provides an opportune time for a woman to make lasting changes to her lifestyle,” says Jessica Marcinkevage MSPH, a PhD student in the Nutrition and Health Sciences Program at Emory’s Rollins School of Public Health and lead researcher for the study. “Implementing a program aimed at healthy weight gain in pregnancy can help alleviate some of the health burdens that disproportionately affect minority women. It can also give her the tools she needs to provide a healthy lifestyle for herself and her family in the years following her pregnancy,”
According to the Institute of Medicine (IOM) how much weight women gain during pregnancy and their starting weight at conception can affect mothers’ health and that of their babies. In 2009, the IOM issued new pregnancy weight gain guidelines which reflect dramatic changes in the population of women having babies in the U.S., using revised body mass index (BMI) categories, and incorporating clear recommendations for obese women.
The new guidelines state healthy women at a normal weight for their height (BMI of 18.5 to 24.9) should gain 25 to 35 pounds during pregnancy. Underweight women (BMI less than 18.5) should gain 28 to 40 pounds, while overweight women (BMI of 25 to 29.9) should stay within 15 to 25 pounds. For women considered obese (BMI greater than 30) the report recommends limiting weight gain to 11 to 20 pounds.
Participants in the study were recruited shortly after their first prenatal care appointment, on average about 12 weeks into their pregnancy. Researchers collected information on baseline body weight and blood pressure, and took blood samples during a sugar tolerance test to assess the functioning of the patient’s pancreas and subsequently her risk for developing diabetes. Participants’ level of physical activity was assessed and dietary intake was evaluated with a 24-hour food recall interview. All of these measures were repeated at 24-28 weeks and 6 weeks post partum.
“While our sample size was small, among women receiving the intervention we saw an indication of improved insulin resistance at 24-28 weeks into pregnancy, as well as improved delivery outcomes when compared with women receiving regular care,” says Marcinkevage. What is more, the intervention program was well received by participants, with many women commenting on how the program provided a unique opportunity to receive information they had never learned before.
The study conclusions state that achieving the IOM recommended weight gain in pregnancy requires individualized attention and support from a woman's prenatal care provider as well as her family and community.
“These efforts can pay off,’ says Umpierrez, “as pregnant women who perform regular exercise and eat healthy diets can limit their risk of gaining too much weight during pregnancy, reducing their chances of developing gestational diabetes and other complications during pregnancy.”