Nutrition and Exercise Reduce Excessive Weight Gain in Normal-Weight Pregnant Women

RUCHAT, S.-M., M. H. DAVENPORT, I. GIROUX, M. HILLIER, A. BATADA, M. M. SOPPER, J. M. S. HAMMOND, and M. F. MOTTOLA. Nutrition and Exercise Reduce Excessive Weight Gain in Normal-Weight Pregnant Women. Med. Sci. Sports Exerc., Vol. 44, No. 8, pp. 1419-1426, 2012. Purpose: This study aimed to evaluate the effect of an exercise program of two different intensities, with nutritional control, on gestational weight gain (GWG), infant birth weight, and maternal weight retention at 2 months postpartum (2 mopp). Methods: Pregnant women (prepregnancy body mass index = 18.5-24.9 kg(.)m(-2)) were randomized at study entry (16-20 wk of gestation) to a low-intensity (LI, 30% HR reserve (HRR), n - 23) or moderate-intensity (MI, 70% HRR, n - 26) exercise program, with nutritional control. The exercise program consisted of walking sessions three to four times per week, gradually increasing exercise time from 25 to 40 min per session. Forty-five normal-weight women who did not participate in any structured exercise program during pregnancy and had singleton births were used as a historical control group. Results: Total GWG was higher in the control group (18.3 +/- 5.3 kg) compared with the LI (15.3 +/- 2.9 kg, P = 0.01) and MI (14.9 +/- 3.8 kg, P = 0.003) groups. During the intervention, GWG was similar in both intervention groups, with weekly rates of weight gain of 0.49 +/- 0.1 and 0.47 +/- 0.1 kg(.)wk(-1) in the LI and MI groups, respectively. Excessive GWG during the intervention was prevented in 70% of the women in the LI group and 77% of those in the MI group. Excessive GWG occurred before the intervention began. At 2 mopp, 18% and 28% of the women in the LI and MI groups, respectively, retained <= 2.0 kg compared with only 7% of those in the control group. Infant birth weight was not different between the groups. Conclusions: Results suggest that a prenatal nutrition and exercise program regardless of exercise intensity, reduced excessive GWG and decreased weight retention at 2 mopp in women of normal weight before pregnancy.