Lifestyle interventions fall short of preventing gestational diabetes

Initiating interventions combining diet and physical activity between 9 and 16 weeks of gestation may attenuate weight gain but not successfully avert the development of gestational diabetes mellitus (GDM), according to data from the LIFE-Moms consortium.

LIFE-Moms comprised 1,148 diabetes-free pregnant women with body mass index (BMI) ≥25 kg/m². The final analysis included 1,005 women assigned to either standard care (n=492) or lifestyle intervention (n=513) early in their pregnancy. They were assessed for GDM at 24–31 weeks of gestation using a 2-hour, 75-gram oral glucose tolerance test (OGTT) or by local clinical practice standards.

At baseline, the women were aged 30.6 years on average. More than half of them (56 percent) were obese. Both fasting plasma glucose and HbA1c were normal (mean, 86.7 mg/dL and 5.3 percent, respectively). The two intervention groups did not differ in terms of maternal age (p=0.33), race/ethnicity (p=0.89), body mass index (p=0.60), gestational age (p=0.19), or glycaemic variables.

Lifestyle interventions reduced early excess gestational weight gain, with a rate of 0.26 kg/week as opposed to 0.35 kg/wk on standard care (p≤0.0001). However, this advantage did not extend to GDM diagnosis.

The proportion of women with GDM at 24–31 weeks of gestation was 11.1 percent in the lifestyle intervention group vs 11.6 percent in the standard care group according to OGTT (p=0.91), and 11 percent vs 13 percent, respectively, according to the International Association of Diabetes and Pregnancy Study Group criteria (p=0.45). The type of diagnostic test did not change the result (p=0.86).

Women who developed GDM had higher BMI and obesity and more likely to have dysglycaemia at baseline.

The findings suggest that in pregnant women who are overweight or obese, factors associated with poor glycaemic control may already be established in the first trimester. More studies are needed to evaluate whether intervention approaches that target hyperglycaemia specifically produce greater benefit for those at high risk of GDM.