Commonly occurring pregnancy complications include gestational diabetes mellitus and gestational hypertension. Evidence to date regarding the effects of exercise on pregnancy complications and outcomes is inconsistent. This systematic review aimed to estimate the effects of aerobic exercise during pregnancy compared to usual care on gestational diabetes mellitus and gestational hypertension.
Six databases were searched for randomised controlled trials (RCTs). There were no language or date restrictions. Eligible studies included pregnant participants with no history of diabetes, hypertension, psychiatric disorders or underlying disease, including cardiac, kidney, liver or reproductive system diseases. The intervention was any type of aerobic exercise. Usual care participants received standard antenatal care and education. The incidence of gestational diabetes mellitus and gestational hypertension were the outcomes of interest. Data extraction and assessment of methodological quality, using the Cochrane Collaboration Risk of Bias tool, were performed by two authors. Study risk of bias was rated as low (if 4 or more criteria were rated as low), medium (if 2-3 criteria were rated as low) or high (if 0-1 criteria were rated as low). A meta-analysis pooled the trials, with forest plots used to summarise and compare trials. A random effects model was used if significant heterogeneity was found (I2>50%).
Eleven trials, involving 3,165 participants were included. Aerobic exercise predominantly included walking and stationary cycling. Yoga was included in three RCTs and a single trial included aquatic jogging and walking. Intervention frequency was commonly 3 days/week for 30-60 minutes duration and 6-40 weeks. Exercise intensity was poorly reported. The majority of trials (8/11) were rated as having a low risk of bias. Blinding of participants and assessors were the items most frequently associated with a higher risk of bias. A minority of trials (3/11) were also at risk of bias due to unclear randomisation and concealed allocation processes.
The aerobic exercise intervention group showed significant reductions in the incidence of gestational diabetes mellitus compared to usual care (OR=0.39, 95% CI 0.30 to 0.50, I2 0%, p<0.00001, 10 trials). Similarly, the incidence of gestational hypertension was significantly reduced favouring the aerobic exercise group (OR=0.38, 95% CI 0.27 to 0.54, I2 0%, p<0.00001, 9 trials). The incidence of adverse events was not reported.
Aerobic exercise during pregnancy reduces the incidence of gestational diabetes mellitus and gestational hypertension. Further research that allows subgroup analysis of the effects of differing exercise modalities and assessment of evidence certainty is required.
Zhang J, Wang H-P, Wang X-X. Effects of aerobic exercise performed during pregnancy on hypertension and gestational diabetes: a systematic review and meta-analysis. J Sports Med Phys Fitness. 2023 Jul;63(7):852-863. doi: 10.23736/S0022-4707.23.14578-6