Written by: Veronica Hackethal MD (July 17,2015)Reporter: Angela Barbie R. Lee

Diet Plus Exercise Doesn’t Prevent Gestational Diabetes

Obesity during pregnancy is currently highest in high-income countries, affecting about 25% of women in the United Kingdom and 34% of women in the United States. This increases the risk for insulin resistance and GDM, which in turn increases the risk for stillbirth, LGA babies, and other birth complications. Children born to mothers with GDM also have a higher risk of metabolic disease in later life.

UK Pregnancies Better Eating and Activity Trial (UPBEAT) reported that behavioral intervention that combines diet and exercise did not prevent gestational diabetes (GDM) or large-for-gestational age (LGA) babies in obese pregnant women, according to results from one of the largest randomized controlled trials to look at this issue.

Definition of Terms:• Gestational diabetes mellitus (GDM) refers to any degree of

glucose intolerance that is detected first during pregnancy • Large for gestational age (LGA) means that a fetus or infant is

larger or more developed than normal for the baby's gestational age. Gestational age is the age of a fetus or baby that starts on the first day of the mother's last menstrual period.•

Research Study:The UPBEAT trial took place between March 2009 and June 2014 at prenatal clinics in eight hospitals in multiethnic inner-city neighborhoods in the United Kingdom. The study included obese pregnant women with a mean body mass index (BMI) of 36.3 kg/m2 (26% of whom were black).

The researchers randomized women to:Group 1: Behavioral Intervention plus standard care (n = 783)Group 2: Standard Prenatal Care (n = 772) Women in the intervention group (Group 1) participated in:health-trainer–led sessions for 1 hour once per week for 8 weeks.These women also received handbooks with recommended foods, recipes, and physical activities, as well as DVDs with exercises safe for pregnancy, a pedometer, and a log book for recording goals.

Group 1: Intervention Group Group 2: Standard Care 160 (25%) developed GDM of 629

(80%) women who took an OGTT in the intervention group.

71 (9%) were LGA of 761 babies born in the intervention group.

Among 651 (84%) women who took an OGTT test in the standard-care group, 172 (26%) developed GDM.

Of 751 babies born in the standard-care group, 61 (8%) were LGA.

*Women took an oral glucose tolerance test (OGTT), and GDM was diagnosed on the basis of criteria from the International Association of Diabetes in Pregnancy Study Group (IADSPG), also adopted by the World Health Organization (WHO).

Lucilla Poston, PhD, from the division of women's health at King's College London, United Kingdom concluded:• While the study found that obese women who take part in a

health-trainer–led program will improve their diet and take more exercise, the benefits of these changes are unlikely to be adequate to reverse the insulin resistance that leads to gestational diabetes.• Compared with the standard-care group, the intervention group

did show improvements in dietary glycemic load, fat intake, activity levels, and a modest decrease in body fat and weight gain (about half a kilogram less than the standard-care group).• Although the intervention did not prevent GDM, it could be of

"general health benefit”.

Shakila Thangaratinam, PhD, MRCOG, professor in maternal and perinatal health at Queen Mary University of London, United Kingdom mentioned:• The National Institute for Health and Care Excellence (NICE) guidelines

recommend referral to a dietician for obese pregnant women but do not recommend regular weighing during pregnancy.• Women should be informed that although a healthy diet and lifestyle

could minimize weight gain in pregnancy, there is no robust evidence for improvement in outcomes such as gestational diabetes or large-for-gestational-age babies.• Reducing excess weight gain during pregnancy, however, could

decrease weight retention after pregnancy and decrease the risk of obesity at the start of future pregnancies, she stresses.• Prevention of obesity needs to be prioritized equally with efforts to

reduce complications in obese pregnant women