1. Women randomized to treatment of mild gestational diabetes were less likely to experience shoulder dystocia, cesarean delivery, gestational hypertensive disease or deliver large for gestational age infants compared to randomized controls.
Original Date of Publication: October 2009
Study Rundown: Gestational diabetes screening was originally developed to identify women at risk for development of diabetes mellitus in the future. As such, the clinical significance of gestational diabetes with regard to maternal and neonatal outcomes, including the impact of treatment, was unknown. In recent years, research better characterized the relationship to demonstrate that even a mild elevation in maternal blood glucose levels was associated with increased risk of fetal macrosomia and associated perinatal complications. However, whether treatment of mild gestational diabetes improves maternal or neonatal outcomes remained unknown. A randomized trial in Australian women recently demonstrated that treatment of mild GDM was associated with a reduced risk of serious perinatal complications. However, as of 2008, the U.S. Preventative Task Force concluded there was insufficient evidence to assess the risk-benefit ratio to screening and treating gestational diabetes. In this multicenter, randomized controlled trial, researchers investigated whether treatment of mild gestational diabetes reduces adverse maternal and fetal outcomes.
This landmark study demonstrated that treating mild gestational diabetes was associated with significant reductions in adverse maternal and fetal outcomes including fetal macrosomia, preeclampsia and labor dystocia leading to cesarean delivery. Findings demonstrated benefit to screening and treating pregnant women with even mild carbohydrate intolerance. Strengths of this investigation included randomized controlled design and strict diagnostic criteria by 3-hour, 100-gram oral glucose tolerance test. An ethnically, geographically and socioeconomically diverse study population allows for reasonably good external validity. Limitations included lack of information on glycemia in controls and a slightly higher percent of women excluded from the control group due to missing delivery data (7% in control group versus 5% in treatment group), although this should not meaningfully impact the direction of the associations identified herein.
Dr. Alan Peaceman, MD, talks to 2 Minute Medicine: Northwestern University School of Medicine; Chief, Division of Obstetrics and Gynecology-Maternal Fetal Medicine.
“This multicenter randomized trial assessed the impact of treatment of mild gestational diabetes on maternal and perinatal outcomes. Findings demonstrate benefit to treating carbohydrate intolerance in pregnancy with reduced risk for adverse delivery and maternal outcomes including maternal preeclampsia, cesarean delivery, and shoulder dystocia.”
In-Depth [randomized controlled trial]: From 2002 through 2007, 7381 women underwent a blinded 3-hour 100g oral glucose-tolerance test at one of the Maternal-Fetal Medicine Units Network clinical centers in this multicenter RCT. A total of women 958 women with mild gestational diabetes from 24 to 31 weeks gestation were randomized to the control group (usual standard of care, n=473) or treatment (dietary intervention, blood glucose self-monitoring and insulin if necessary, n=485) to evaluate the clinical impact of treatment of mild gestational diabetes mellitus. Outcomes assessed included a composite of stillbirth or neonatal death and neonatal complications (hyperbilirubinemia, hypoglycemia, hyperinsulinemia and birth trauma). Neonatal birthweight, shoulder dystocia, cesarean delivery, gestational hypertension and pre-eclampsia were also evaluated.
Women with mild gestational diabetes randomized to treatment were less likely to experience gestational hypertension or pre-eclampsia (8.6% vs. 13.6%, p=0.01), shoulder dystocia (1.5% vs. 4.0%, p=0.02), cesarean delivery (27% vs. 34%, p=0.02) or to deliver large for gestational age infants (7 vs 15%, p<0.001). Women in the treatment group also experienced less weight gain in pregnancy (2.8kg vs. 5.0kg, p<0.001). The primary outcome of composite neonatal morbidity and mortality, including stillbirth and perinatal death, did not differ between treatment and control groups (p=0.14).
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