A behavioral intervention focusing on diet and exercise did not prove effective in preventing gestational diabetes or reducing the incidence of large-for-gestational-age babies in high-risk obese women, new data published in The Lancet Diabetes & Endocrinology indicate.
“The increasing global problem of obesity in maternity care has led to national guideline recommendations for the development of interventions to improve pregnancy outcomes. This advice stimulated many clinical trials, predominantly of behavioral interventions addressing diet and physical activity,” the researchers wrote.
Even so, many of those trials were underpowered for clinical outcomes such as gestational diabetes and focused on preventing gestational weight gain, they noted. However, reviews of small trials suggest that behavior change interventions may help prevent gestational diabetes in obese pregnant women.
In the UK Pregnancies Better Eating and Activity Trial (UPBEAT), the researchers randomly assigned more than 1,500 women (mean BMI, 36.3) from eight inner-city antenatal services providing care to multi-ethnic populations of generally high socioeconomic deprivation to a behavioral intervention (n=783) or standard antenatal care (n=772).
The behavioral intervention involved eight health trainer-led sessions that occurred once a week. Participants received a handbook with recommended foods, recipes and physical activity as well as a DVD of an exercise regime safe for pregnancy, a pedometer and a log book to record weekly goals.
Increasing the amount of walking at a moderate intensity was the primary exercise goal. Selecting foods with a lower glycemic index and limiting saturated fat intake served as the foundation for the healthier diet.
Women underwent glucose tolerance tests, but the WHO-recommended criteria were used to diagnose gestational diabetes and implement treatment.
Although the researchers observed improvements in maternal outcomes in the intervention group, such as decreased dietary glycemic load, gestational weight gain and maternal sum-of-skinfold thicknesses, and increased physical activity, they found no significant differences in the primary outcomes of gestational diabetes and large-for-gestational age babies.
Of all participants, 332 (26%) developed gestational diabetes — 172 (26%) in the standard care group and 160 (25%) in the intervention group (risk ratio, 0.96; 95% CI, 0.79-1.16), according to the data.
Sixty-one of 751 babies (8%) born to mothers in the standard care group were large for gestational age, and 71 of 761 (9%) born to mothers in the intervention group were large for gestational age (risk ratio, 1.15; 95% CI, 0.83-1.59).
In terms of adverse events, two neonatal deaths occurred in the standard care group and three in the intervention group, and 10 fetal deaths in utero occurred in the standard care group and six in the intervention group. Incidence of miscarriage was 2% in the standard care group and 2% in the intervention group.
“Our study shows that an intensive diet and exercise regime alone cannot help reduce the risk of developing gestational diabetes in obese women. However, using a more stringent diagnostic test for gestational diabetes meant we picked up more cases. We believe the greater number of women treated as a result of this test may explain why our study found a lower than anticipated incidence of [large-for-gestational-age] infants in all women,” study researcher Lucilla Poston, PhD, of the division of women’s health at King’s College London, said in a press release.
“This has implications for the diagnosis of gestational diabetes in the UK as NICE have recently decided against adoption of the WHO (IADPSG) criteria.”
Although the intervention did not have the intended effect, Poston pointed out that there were certain benefits that may help improve other outcomes.
“Whilst the intervention did not prevent gestational diabetes, the UPBEAT study provides a new and effective strategy to improve diet and physical activity in obese pregnant women adoptable in a UK health care setting,” Poston said. “We are now following the mothers and children from this cohort to see whether changes in the mothers’ diet and activity are sustained and have an effect on their health and that of their offspring.”