Inositol for the prevention of gestational diabetes: a systematic review and meta-analysis of randomized controlled trials

Purpose: Inositol (ISL) embraces a family of simple carbohydrates with insulin-sensitizing properties, whose most common isoforms are Myo-inositol (MYO) and d-chiro inositol (DCI). The aim of the present study was to assess the efficacy and safety of ISL supplementation during pregnancy for the prevention of gestational diabetes (GDM). Methods: We conducted a systematic literature search in electronic databases until October 2017. We included all randomized controlled trials (RCTs) comparing pregnant women with GDM who were randomized to either ISL (i.e., intervention group) or either placebo or no treatment (i.e., control group). The primary outcome was the preventive effect on GDM, defined as the rate of GDM in women without a prior diagnosis of GDM. Pooled results were expressed as odds ratio (OR) with a 95% confidence interval (95% CI). Results: Five RCTs were included (including 965 participants). ISL supplementation was associated with lower rate of GDM (OR 0.49, 95% CI 0.24–1.03, p = 0.01) and lower preterm delivery rate (OR 0.35, 95% CI 0.17–0.74, p = 0.006). No adverse effects were reported. Adjusting for the type of intervention (MYO 2 g twice daily vs MYO 1100 mg plus DCI 27.6 mg daily), a significant effect was found only in patients receiving 2 g MYO twice daily. Conclusions: ISLs administration during pregnancy appears to be safe and may represent a novel strategy for GDM prevention. In particular, the double administration of MYO 2 g per day may improve the glycemic homeostasis and may reduce GDM rate and preterm delivery rate.