Exercise for pregnant women with gestational diabetes for improving maternal and fetal outcomes

Background Gestational diabetes mellitus (GDM) is associated with both short‐ and long‐term complications for the mother and her baby. Exercise interventions may be useful in helping with glycaemic control and improve maternal and infant outcomes. The original review on Exercise for diabetic pregnant women has been split into two new review titles reflecting the role of exercise for pregnant women with gestational diabetes and for pregnant women with pre‐existing diabetes. Exercise for pregnant women with gestational diabetes for improving maternal and fetal outcomes (this review) Exercise for pregnant women with pre‐existing diabetes for improving maternal and fetal outcomes Objectives To evaluate the effects of exercise interventions for improving maternal and fetal outcomes in women with GDM. Search methods We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (27 August 2016), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (18th August 2016), and reference lists of retrieved studies. Selection criteria We included randomised controlled trials (RCTs) comparing an exercise intervention with standard care or another intervention in pregnant women diagnosed with gestational diabetes. Quasi‐randomised and cross‐over studies, and studies including women with pre‐existing type 1 or type 2 diabetes were not eligible for inclusion. Data collection and analysis All selection of studies, assessment of trial quality and data extraction was conducted independently by two review authors. Data were checked for accuracy. Main results We included 11 randomised trials, involving 638 women. The overall risk of bias was judged to be unclear due to lack of methodological detail in the included studies. For the mother, there was no clear evidence of a difference between women in the exercise group and those in the control group for the risk of pre‐eclampsia as the measure of hypertensive disorders of pregnancy (risk ratio (RR) 0.31, 95% confidence interval (CI) 0.01 to 7.09; two RCTs, 48 women; low‐quality evidence), birth by caesarean section (RR 0.86, 95% CI 0.63 to 1.16; five RCTs, 316 women; I2 = 0%; moderate‐quality evidence), the risk of induction of labour (RR 1.38, 95% CI 0.71 to 2.68; one RCT, 40 women; low‐quality evidence) or maternal body mass index at follow‐up (postnatal weight retention or return to pre‐pregnancy weight) (mean difference (MD) 0.11 kg/m2, 95% CI ‐1.04 to 1.26; three RCTs, 254 women; I2 = 0%; high‐quality evidence). Development of type 2 diabetes, perineal trauma/tearing and postnatal depression were not reported as outcomes in the included studies. For the infant/child/adult, a single small (n = 19) trial reported no perinatal mortality (stillbirth and neonatal mortality) events in either the exercise intervention or control group (low‐quality evidence). There was no clear evidence of a difference between groups for a mortality and morbidity composite (variously defined by trials, e.g. perinatal or infant death, shoulder dystocia, bone fracture or nerve palsy) (RR 0.56, 95% CI 0.12 to 2.61; two RCTs, 169 infants; I2 = 0%; moderate‐quality evidence) or neonatal hypoglycaemia (RR 2.00, 95% CI 0.20 to 20.04; one RCT, 34 infants; low‐quality evidence). None of the included trials pre‐specified large‐for‐gestational age, adiposity (neonatal/infant, childhood or adulthood), diabetes (childhood or adulthood) or neurosensory disability (neonatal/infant) as trial outcomes. Other maternal outcomes of interest: exercise interventions were associated with both reduced fasting blood glucose concentrations (average standardised mean difference (SMD) ‐0.59, 95% CI ‐1.07 to ‐0.11; four RCTs, 363 women; I2 = 73%; T2 = 0.19) and a reduced postprandial blood glucose concentration compared with control interventions (average SMD ‐0.85, 95% CI ‐1.15 to ‐0.55; three RCTs, 344 women; I2 = 34%; T2 = 0.03). Authors' conclusions Short‐ and long‐term outcomes of interest for this review were poorly reported. Current evidence is confounded by the large variety of exercise interventions. There was insufficient high‐quality evidence to be able to determine any differences between exercise and control groups for our outcomes of interest. For the woman, both fasting and postprandial blood glucose concentrations were reduced compared with the control groups. There are currently insufficient data for us to determine if there are also benefits for the infant. The quality of the evidence in this review ranged from high to low quality and the main reason for downgrading was for risk of bias and imprecision (wide CIs, low event rates and small sample size). Development of type 2 diabetes, perineal trauma/tearing, postnatal depression, large‐for‐gestational age, adiposity (neonate/infant, childhood or adulthood), diabetes (childhood or adulthood) or neurosensory disability (neonate/infant) were not reported as outcomes in the included studies. Further research is required comparing different types of exercise interventions with control groups or with another exercise intervention that reports on both the short‐ and long‐term outcomes (for both the mother and infant/child) as listed in this review.