BACKGROUND: Transmission of obesity across generations is of concern. Offspring of obese women have short- and long-term increased morbidities. A high intake of carbohydrate during pregnancy combined with impaired glucose tolerance is postulated to result in high birth weight, which is linked to subsequent metabolic disease.

OBJECTIVE: The objective was to examine the association between carbohydrate intake in obese pregnant women and their offspring's body composition.

DESIGN: Secondary analyses were performed in an observational setting of 222 pregnant women with a pregestational BMI (in kg/m(2)) ≥30 participating in a randomized controlled trial. Diet was assessed at gestational weeks 11-14 and 36-37 by using a semiquantitative food-frequency questionnaire. Body composition in the offspring was assessed at birth by dual-energy X-ray absorptiometry. Relative fat mass (%) was the primary outcome. Absolute measures (total fat, abdominal fat, and lean body mass) were secondary outcomes.

RESULTS: Mean ± SD weight and absolute and relative fat mass in the offspring at birth were 3769 ± 542 g, 436 ± 214 g, and 11% ± 4%, respectively. Maternal intake of digestible carbohydrates was associated with the offspring's relative fat mass in late (P-trend = 0.006) but not early (P-trend = 0.15) pregnancy. A comparison of mothers in the highest (median: 238 g/d) compared with the lowest (median: 188 g/d) quartile of digestible carbohydrate intake showed a mean adjusted higher value in the offspring's relative fat mass of 2.1% (95% CI: 0.6%, 3.7%), which corresponded in absolute terms to a 103-g (95% CI: 27, 179-g) higher fat mass. Abdominal fat mass was also higher. In a strata of women with well-controlled glucose (2-h glucose values ≤6.6 mmol/L), no association between carbohydrate intake and offspring fat mass was observed, but the associations became significant and increased in strength with higher intolerance (strata with 2-h glucose values between 6.7-7.7 and ≥7.8 mmol/L).

CONCLUSION: In obese women, even those without gestational diabetes but with impaired glucose tolerance, a lower carbohydrate intake at moderate levels in late gestation is associated with a lower fat mass in their offspring at birth. The TOP study was registered at clinicaltrials.gov as NCT01345149.