A randomized trial of the effects of dietary counseling on gestational weight gain and glucose metabolism in obese pregnant women.

Objective: Can gestational weight gain in obese women be restricted by 10-h dietary consultations and does this restriction impact the pregnancy-induced changes in glucose metabolism?

Design: A randomized controlled trial with or without restriction of gestational weight gain to 6-7 kg by ten 1-h dietary consultations.

Subjects: Fifty nondiabetic nonsmoking Caucasian obese pregnant women were randomized into intervention group (n=23, 28+/-4 years, prepregnant body mass index (BMI) 35+/-4 kg m(-2)) or control group (n=27, 30+/-5 years, prepregnant BMI 35+/-3 kg m(-2)).

Measurements: The weight development was measured at inclusion (15 weeks), at 27 weeks, and 36 weeks of gestation. The dietary intakes were reported in the respective weeks by three 7-day weighed food records and blood samples for analyses of fasting s-insulin, s-leptin, b-glucose, and 2-h b-glucose after an oral glucose tolerance test were collected.

Results: The women in the intervention group successfully limited their energy intake, and restricted the gestational weight gain to 6.6 kg vs a gain of 13.3 kg in the control group (P=0.002, 95% confidence interval (CI): 2.6-10.8 kg). Both s-insulin and s-leptin were reduced by 20% in the intervention group compared to the control group at week 27, mean difference: -16 pmol l(-1) (P=0.04, 95% CI: -32 to -1) for insulin and -23 ng ml(-1) (P=0.004, 95% CI: -39 to -8) for leptin. At 36 weeks of gestation, the s-insulin was further reduced by 23%, -25 pmol l(-1) (-47 to -4, P=0.022) and the fasting b-glucose were reduced by 8% compared with the control group (-0.3 mmol l(-1), -0.6 to -0.0, P=0.03).

Conclusions: Restriction of gestational weight gain in obese women is achievable and reduces the deterioration in the glucose metabolism.