Comment: The quality of evidence is downgraded by study limitations (unclear allocation concealment and blinding of outcome assessment).
Clinical comment: In most studies the intervention was started late in gestation or the time was not stated.
A meta-analysis and meta-regression «...»2 included 24 RCTs with a total of 3477 participants. Exercise lowered fasting blood glucose (FBG) (SMD -1.69, I²=96 %, p < 0.0001), 2-h postprandial blood glucose (2-hPBG) (SMD -2.10, I²=96 %, p < 0.0001), and glycated hemoglobin (MD -0.95, I²=98 %, p < 0.0001), although with high heterogeneity. Exercise reduced the risk of gestational hypertension (RR 0.24, I²=0 %, p < 0.0001), caesarean section (RR 0.71, I²=53 %, p = 0.0005), preterm birth (RR 0.51, I²=31 %, p = 0.002), macrosomia (RR 0.40, I²=19 %, p < 0.0001), and neonatal hypoglycemia (RR 0.49, I²=0 %, p = 0.03). Subgroup analyses indicated that moderate combined aerobic and resistance exercise improved FBG, 2-hPBG and the risks of cesarean section, preterm birth, and macrosomia. There was a significant dose-response relationship between exercise volume and 2-hPBG. The analysis found improvements, when exercise lasted at least 30 min per session, more than 3 times per week, for at least 6 weeks. All types of exercise were effective but combined aerobic and resistance exercise produced the greatest effect size.
A systematic review and Bayesian network meta-analysis «...»3 included 39 RCTs with information obtained from 2712 women assessing 15 treatments. Dietary approaches to stop hypertension (DASH) diet emphasizes the consumption of fruits, vegetables, whole grains, legumes, nuts, lean protein, and low-fat dairy products. The DASH diet and resistance exercise reduced insulin requirements independently by 71% (95% credible intervals [CrI] 52% to 84%) and 67% (95% CrI 48% to 85%), respectively. Both the DASH (MD -587.6; 95% CrI: -752.12 to -421.85) and low glycaemic index diets (MD -180.09, 95% CrI: -267.48 to -94.65) reduced birth weight (low evidence). The DASH diet reduced macrosomia by 89% (95% CrI: 53% to 98%) and lowered the caesarean section rate by 46% (95% CI: 27% to , 60%).
A systematic review and meta-analysis «...»4 included 17 studies (15 RCTs, 2 cohort studies). Exercise reduced the risk of adverse neonatal outcomes: Cesarean delivery (OR 0.91, 95% CI 0.88 to 0.94), premature birth (OR 0.49, 95% CI 0.27 to 0.90), macrosomia (OR 0.58, 95% CI 0.40 to 0.83), fetal growth restriction (OR 0.21, 95% CI 0.08 to 0.52), and birth trauma (OR 0.26, 95% CI 0.13 to 0.54).
A Cochrane review «Lifestyle interventions for the treatment of women with gestational diabetes»1 «Brown J, Alwan NA, West J et al. Lifestyle interve...»1 included 15 studies with a total of 4501 women and 3768 infants. The lifestyle interventions included a wide variety of components such as education, diet, and exercise. There was no clear evidence of a difference between lifestyle intervention and control groups (usual care or diet alone) for the risk of hypertensive disorders of pregnancy (pre-eclampsia), caesarean section, development of type 2 diabetes, perineal trauma/tearing, or induction of labour «Lifestyle interventions versus control - Maternal outcomes...»1. More women in the lifestyle intervention group had met postpartum weight goals one year after birth than in the control group «Lifestyle interventions versus control - Maternal outcomes...»1. Lifestyle interventions were associated with a reduction in the risk of being born large-for-gestational age (LGA) «Lifestyle versus control - Neonatal and later outcomes...»2. There was a trend for lower birthweight, neonatal fat mass, and the incidence of macrosomia in the lifestyle intervention group «Lifestyle versus control - Neonatal and later outcomes...»2.
| Outcomes | Relative effect (95% CI) | Risk with usual care/control | Risk with lifestyle intervention (95% CI) | № of participants (studies) Quality of evidence |
|---|---|---|---|---|
| Hypertensive disorders of pregnancy (pre-eclampsia) | RR 0.70 (0.40 to 1.22) | 129 per 1000 | 90 per 1000 (51 to 157) | (4 2796) Low |
| Perineal trauma/tear | RR 1.04 (0.93 to 1.18) | 498 per 1000 | 518 per 1000 (463 to 588) | 1000 (1) Moderate |
| Caesarean section | RR 0.90 (0.78 to 1.05) | 380 per 1000 | 342 per 1000 (296 to 399) | 3545 (10) Low |
| Induction of labour | RR 1.20 (0.99 to 1.46) | 211 per 1000 | 252 per 1000 (220 to 285) | 2699 (4) High |
| Postnatal depression | RR 0.49 (0.31 to 0.78) | 169 per 1000 | 83 per 1000 (53 to 132) | 573 (1) Low |
| Postnatal weight retention or return to pre-pregnancy weight | RR 1.75 (1.05 to 2.90) | 214 per 1000 | 375 per 1000 (225 to 621) | 156 (1) Low |
| Development of type 2 diabetes (follow-up) | RR 0.98 (0.54 to 1.76) | 83 per 1000 | 81 per 1000 (45 to 146) | 486 (2) Low |
| Outcomes | Relative effect (95% CI) | Risk with usual care/control | Risk with lifestyle intervention (95% CI) | № of participants (studies) Quality of evidence |
|---|---|---|---|---|
| Large-for-gestational age | RR 0.60 (0.50 to 0.71) | 189 per 1000 | 113 per 1000 (95 to 134) | 2994 (6) Moderate |
| Perinatal (fetal and neonatal death) and later infant mortality | RR 0.09 (0.01 to 1.70) | 5 per 1000 | 0 per 1000 (0 to 9) | 1988 (2) Low |
| Neonatal hypoglycaemia | RR 0.99 (0.65 to 1.52) | 75 per 1000 | 74 per 1000 (49 to 114) | 3000 (6) Moderate |
| Adiposity (neonatal) - Mean neonatal fat mass (g) | - | 427 g | 37.30 g fewer (63.97 fewer to 10.63 fewer) - | 958 (1) Low |
| Adiposity (child) - Childhood BMI > 85th percentile | RR 0.91 (0.75 to 1.11) | 350 per 1000 | 318 per 1000 (262 to 388) | 767 (3) Moderate |