A systematic review and meta-analysis 10 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 (OR, 0.61; 95% CI, 0.45 to 0.82), preterm delivery (OR, 0.43; 95% CI, 0.22 to 0.84), large for gestational age neonate (OR, 0.19; 95% CI, 0.08 to 0.47), neonatal intensive care admission (OR, 0.68; 95% CI, 0.48 to 0.95), and total adverse maternal (OR, 0.75; 95% CI, 0.61 to 0.92) and neonatal outcomes (OR, 0.44; 95% CI, 0.26 to 0.72). Physical activity was associated with reduced GWG and reduced risk of GDM (OR, 0.60; 95% CI, 0.47 to 0.75), hypertensive disorders (OR, 0.66; 95% CI, 0.48 to 0.90), cesarean section (OR, 0.85; 95% CI, 0.75 to 0.95), and total adverse maternal outcomes (OR, 0.78; 95% CI, 0.71 to 0.86). Diet with physical activity was associated with reduced GWG (-1.35 kg; 95% CI, -1.95 to -0.75) and GDM (OR, 0.72; 95% CI, 0.54 to 0.96) and total adverse maternal outcomes (OR, 0.81; 95% CI, 0.69 to 0.95).
A Cochrane review [Abstract] 1 included 5 studies with a total of 1115 women and their babies. 4 of the 5 included trials had small sample sizes with one large trial that recruited 855 women. The used interventions in the different trials were 35-45 -minutes supervised sessions 3 times a week, an individualised exercise plan with an energy expenditure goal of 900 kcal per week, home-based stationary cycling for a maximum of 5 sessions of 40 minutes aerobic exercise per week, home-based supervised stationary cycling for 3 sessions of 25 minutes, or a weekly supervised 60-minute group exercise session plus a 45-minute home exercise program at least twice per week The length of the exercise period varied. When comparing women receiving additional exercise interventions with those having routine antenatal care, there was no significant difference in gestational diabetes mellitus (GDM) incidence (RR 1.10, 95% CI 0.66 to 1.84; 3 trials, n=826), caesarean section (RR 1.33, 95% CI 0.97 to 1.84; 2 trials, n=934) or operative vaginal birth (RR 0.83, 95% CI 0.58 to 1.17; 2 trials, n=934). No trial reported the infant primary outcomes prespecified in the review. None of the 5 included trials found significant differences in insulin sensitivity. Evidence from one single large trial suggested no significant difference in the incidence of developing pregnancy hyperglycaemia not meeting GDM diagnostic criteria, pre-eclampsia or admission to neonatal ward between the two study groups.
Another Cochrane review [Abstract] 2 included 23 studies with a total of 8 918 women and their babies. When a diet and exercise intervention was compared with no intervention, there was a trend towards lower risk of GDM and caesarean section (table T1). No difference was found in pre-eclampsia, high blood pressure, a large for age baby at birth, or perineal trauma. Reduced weight gain during pregnancy was shown for women receiving the combined diet and exercise intervention (table T1).
| Outcome | Relative effect (95% CI) | Risk with control - Standard care | Risk with intervention - Diet and exercise interventions (95% CI) | №of participants (RCTs) Quality of evidence |
|---|---|---|---|---|
| GDM | RR 0.85(0.71 to 1.01) | 168 per 1000 | 143 per 1000(119 to 170) | 6633(19) Moderate |
| Hypertensive disorders (pre-eclampsia) | RR 0.98(0.79 to 1.22) | 57 per 1000 | 55 per 1000(45 to 69) | 5366(8) Low |
| Hypertensive disorders (pregnancy-induced hypertension/hypertension) | RR 0.78 (0.47 to 1.27) | 103 per 1000 | 80 per 1000(48 to 130) | 3073 (6) Very low |
| Caesarean section | RR 0.95(0.88 to 1.02) | 299 per 1000 | 284 per 1000(263 to 305) | 6089(14) Moderate |
| Gestational weight gain (kg) | MD - 0.89 (-1.39 to - 0.40) | The mean gestational weight gain was 0.89 kg less (1.39 kg less to 0.40 kg less) | 5052 (16) Moderate |
A meta-analysis 6 included 8 trials with a total of 2981 normal-weight women. Exercise was started at week 6-14 (in one trial week 20-36) and continued to the end of third trimester 3 times a week. The occurrence of GDM was reduced (RR 0.58, 95% CI 0.37 to 0.90, P = 0.01 and RR 0.60, 95% CI 0.36 to 0.98, P = 0.04 based on different diagnosis criteria, respectively).
An RCT 9 randomized 293 women with a history of GDM and/or a prepregnancy BMI of ≥30 at <20 weeks of gestation to the intervention group or the control group. The incidence of GDM was reduced in the intervention group compared to the control group (13.9% vs 21.6 %, RR 0.61, 95% CI 0.40 to 0.98%; P = 0.044, after adjustment for age, prepregnancy BMI, previous GDM status, and the number of weeks of gestation). Women in the intervention group increased their leisure time physical activity more and improved their dietary quality compared with women in the control group.
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%), cesarean 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 cesarean 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 cesarean delivery was decreased by 16% in the exercise group.
Yet another meta-analysis 8 included 106 RCTs involving 273 182 participants. Exercise-only interventions reduced odds of GDM (OR 0.62, 95% CI 0.52 to 0.75, n=6934), gestational hypertension (OR 0.61, 95% CI 0.43 to 0.85, n=5316) and pre-eclampsia (OR 0.59, 95% CI 0.37 to 0.9, n=3322) compared with no exercise. To achieve at least a 25% reduction in the odds of developing GDM, pre-eclampsia and gestational hypertension, pregnant women need to accumulate at least 600 MET-min/week of moderate-intensity exercise (eg, 140 min of brisk walking, water aerobics, stationary cycling or resistance training).
Yet another meta-analysis 7 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 %.
The time period for the exercise might be too short to produce a difference in the outcomes.
Date of latest search:2022-04-27
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