D-Chiro Inositol Supplementation and the Occurrence of Gestational Diabetes: A Randomized Controlled Trial in China

To investigate the effect of D-chiro inositol (DCI) supplementation on perinatal outcomes in pregnant women at high risk of gestational diabetes mellitus (GDM), we conducted a prospective, randomized, placebo-controlled study. Eligibility criteria included women aged ≥ 35 years old, with a pre-pregnancy body mass index ≥ 24 kg/m², having a family history of type 2 diabetes, having a history of GDM, polycystic ovary syndrome, or a history of delivering macrosomia infants. Participants who were recruited at a gestational age of 12-16 weeks, were randomly to receive either DCI 500 mg twice daily or to receive a placebo for 12 weeks. Outcome measured included the occurrence of GDM and other perinatal outcomes. Between 2020 and 2022, 276 participants were enrolled, with 139 in the DCI Group and 137 in the Control Group. Occurrence of GDM was significantly lower in the DCI group compared to that in placebo group (24.8% vs. 38.1%, p = 0.027). A significant difference was observed in the 1-h glycemia during the oral glucose tolerance test (OGTT) (8.35 ± 1.55 vs. 8.81 ± 1.85, p = 0.043), however, no significant differences in the fasting glucose level or 2-h glycemia between the two groups. The mean birth weight of newborns in the control group was significantly heavier than in the DCI group (3487.9 ± 437.7 g vs. 3341.6 ± 420.1 g, p = 0.011). Therefore, DCI supplementation in early pregnancy can reduce the occurrence of GDM in women at high risk. Trial Registration: ClinicalTrials.gov identifier: NCT 04801485.