medwireNews: The two diabetes-related Cochrane reviews published in November focus on the prevention and treatment of gestational diabetes.
The first is an update of a 2015 review of the effects of diet and exercise in preventing gestational diabetes and associated complications. The review authors – Emily Shepherd (University of Adelaide, South Australia) and colleagues – had previously concluded that there was insufficient evidence.
However, having included an additional 10 studies in the updated review, to give 23 studies in total with data from 8918 women and 8709 infants, they now conclude that diet and exercise may reduce the risk for gestational diabetes and for cesarean section. Specifically, there were potential 15% and 5% reductions in the risk for gestational diabetes and cesarean section, respectively, although in both cases the 95% confidence intervals did not exclude no effect.
There were no clear effects for other outcomes, including preeclampsia, infants being born large for gestational age, neonatal hypoglycemia, or childhood adiposity.
The diet and exercise interventions were mostly aimed at limiting weight gain during pregnancy, and women assigned to the interventions did indeed gain significantly less weight than those in the control groups, by an average of 0.89 kg.
However, the review authors note that the evidence was largely of moderate quality and say: “Due to the variability of the diet and exercise components tested in the included studies, the evidence in this review has limited ability to inform practice.”
The second review, which is a new one, examines use of insulin to treat gestational diabetes and concludes that is it, broadly speaking, no better or worse than using oral antidiabetic agents. Insulin was associated with a 1.89-fold increased risk for hypertensive disorders of pregnancy (but not for preeclampsia specifically), an average 1.06 kg greater weight gain, and a possible increased risk for induction of labor, with this last observed in three studies that used metformin as the comparator.
But maternal and infant outcomes did not otherwise differ with insulin versus oral antidiabetic agents (most commonly metformin and/or glibenclamide) across the 53 included studies, which contained data from 7381 women and 6435 infants.
Julie Brown (University of Auckland, New Zealand) and co-authors therefore conclude: “The choice of insulin or oral anti-diabetic pharmacological therapies could be based on informed consultation with the woman and include preference, compliance, cost, accessibility to medication and control of maternal hyperglycaemia.”
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