Interventions for Preventing Excessive Weight Gain during Pregnancy

Summary

A Cochrane review [Abstract] 1 included 49 studies with a total of 11 444 subjects. Diet or exercise, or both, interventions reduced the risk of excessive gestational weight gain on average by 20% overall (high-quality evidence) T1. Interventions involving low glycaemic load diets, supervised or unsupervised exercise only, or diet and exercise combined all led to similar reductions in the number of women gaining excessive weight in pregnancy.However, there was no significant difference between intervention and control groups with regard to pre-eclampsia, caesarean delivery, preterm birth overall, infant macrosomia, or poor neonatal outcomes including shoulder dystocia, neonatal hypoglycaemia, hyperbilirubinaemia, or birth trauma T1.

A meta-analysis 2 included 23 RCTs with a total of 4462 pregnant women. Compared with women having conventional medical care, gestational weight gain was significantly decreased in women with physical exercise (weighted mean difference [WMD] -1.02, 95% CI -1.35 to -0.70; P < .01; I = 48.4%]. Women appeared to benefit more for gestational weight control of exercise frequency of 3 times per week (WMD -1.22, 95% CI -1.55 to -0.90; I = 40.3%) and exercise duration of 30 to 45 minutes each time (WMD -1.32, 95% CI -1.79 to -0.85; I = 1.5%).

An RCT 3 included 300 chinese owerweight or obese women at 10 weeks' gestational age. Women in the exercise group were cycling at least 30 min/session 3 times per week until 37 weeks of gestation. Those in the control group continued their usual daily activities. Incidence of gestational diabetes mellitus was lower inthe exercise group (22.0% vs 40.6%; P < 0.001). These women also had significantly less gestational weight gain by 25 gestational weeks and at the end of pregnancy (8.38 ± 3.65 vs 10.47 ± 3.33 kg; P < 0.001) and reduced insulin resistance levels at 25 gestational weeks. There were less hypertensive disorders of pregnancy (17.0% vs 19.3%), caesarean delivery (29.5% vs 32.5%), macrosomia (defined as birthweight >4000 g) (6.3% vs 9.6%) and large-for-gestational-age infants (14.3% vs 22.8%), but without significant difference.

A meta-analysis 4 evaluating the effects of exercise during pregnancy on the risk of preterm birth included 2059 women. 1022 women (49.6%) were randomized to the exercise group: Aerobic exercise lasted about 35-90 minutes 3-4 times per week. Compared to control group, women in the exercise group had a similar incidence of preterm birth of <37 weeks (4.5% vs 4.4%; RR 1.01, 95% CI, 0.68 to1.50). Women in the exercise group had a significantly higher incidence of vaginal delivery (73.6% vs 67.5%; RR 1.09, 95% CI 1.04 to 1.15) and a lower incidence of caesarean delivery (17.9% vs 22%; RR 0.82, 95% CI 0.69 to 0.97), gestational diabetes mellitus (2.9% vs 5.6%; RR 0.51, 95% CI 0.31 to 0.82) and hypertensive disorders (1.0% vs 5.6%; RR 0.21, 95% CI 0.09 to 0.45) compared with controls.

Another meta-analysis 5 included 17 trials with a totat of 5075 pregnant women. Women who were randomized in early pregnancy to aerobic exercise for about 30-60 min 2 to 7 times per week had a significant lower incidence of gestational hypertensive disorders (5.9% vs. 8.5%; RR 0.70, 95% CI 0.53 to 0.83; 7 studies, n=2517), specifically a lower incidence of gestational hypertension (2.5% vs. 4.6%; RR 0.54, 95% CI 0.40 to 0.74; 16 studies, n=4641) compared with controls. The incidence of pre-eclampsia (2.3% vs. 2.8%; RR 0.79, 95% CI 0.45 to 1.38; 6 studies, n=2230) was similar in both groups. The incidence of caesarean delivery was decreased by 16% in the exercise group.

Yet another meta-analysis 6 included 47 RCTs involving 15 745 participants. Compared with standard care, the overall effect size of diet, exercise, and mixed interventions during pregnancy was a 23% reduction in the risk of GDM (RR 0.77, 95% CI 0.69 to 0.87; 18 trials, P < 0.0001, I²=40%). An exercise intervention resulted in an RR of 0.70 (95% CI 0.59 to 0.84; 19 trials, n=5883, I²=14.9%), a diet intervention resulted in an RR of 0.75 (95% CI 0.59 to 0.95; 11 trials, n=2838, I²=32,7%). The key aspects improving the preventive effect were: targeting the high-risk population; an early initiation of the intervention; the correct intensity and frequency of exercise; and gestational weight gain management. Exercise of moderate intensity for 50-60 minutes twice a week reduced GDM approximately by 24 %.

A systematic review and meta-analysis 7 evaluating the association of different types of diet and physical activity-based antenatal lifestyle interventions with gestational weight gain (GWG) and maternal and neonatal outcomes included 117 RCTs with a total of 34 546 women. Compared with routine care, diet was associated with less GWG (-2.63 kg; 95% CI, -3.87 to -1.40) than physical activity (-1.04 kg; 95% CI, -1.33 to -0.74) or mixed interventions (eg, unstructured lifestyle support, written information with weight monitoring, or behavioral support alone) (-0.74 kg; 95% CI, -1.06 to -0.43). Diet was associated with reduced risk of GDM, preterm delivery, large for gestational age neonate, neonatal intensive care admission, and total adverse maternal, and neonatal outcomes. Physical activity was associated with reduced GWG and reduced risk of GDM, hypertensive disorders, cesarean section, and total adverse maternal outcomes.