An early, customized low-glycemic-index diet prevents adverse pregnancy outcomes in overweight/obese women.

Background: To determine whether the prescription and follow-up of a behavioral program (customized nutritional advices and a constant physical activity) influences the occurrence of unfavorable maternal/neonatal outcomes among overweight/obese women.

Methods: A case-control study (1:3) included single pregnant women with Body Mass Index (BMI) ≥25 kg/m2, enrolled at 1st trimester. Cases (N.=95) were prescribed (by both the dietitian and gynecologist) a low-glycemic-index diet with an average intake of 1700/1800 kcal/day plus 30 minutes of walking at least 3 times/week (with four follow-up visits until delivery). Controls (N.=275) received a nutritional booklet about a healthy lifestyle, then attended their scheduled visits until delivery by the obstetricians in charge.

Results: Gestational weight gain was similar between groups, despite obese women were higher in cases (67.4%) than in controls (54.5%, P=0.029). The occurrence of gestational diabetes mellitus (GDM) was lower in cases (21.5%) than in controls (32.7%; P=0.041). Such reduction remained related with the group of intervention (P=0.004) after correcting for confounders (BMI≥30 kg/m2, a family history of diabetes, age ≥35 and ethnicity). A higher number of controls developed pregnancy induced hypertension (PIH) (11.6% vs. 1.1% in cases, P<0.001). Preterm birth (PTB) occurred in one case and in 28 controls (10.2%; P=0.004). In half of them, PTB was spontaneous while medically indicated for intrauterine growth restriction, hemorrhage, PIH, GDM/macrosomia, Rh isoimmunization in the remnant.

Conclusions: An early behavioral intervention among overweight/obese pregnant women reduces unfavorable pregnancy outcomes.