Gestational Diabetes Mellitus in Early Pregnancy: Evidence for Poor Pregnancy Outcomes Despite Treatment.

OBJECTIVE Recent guidelines recommend testing at <24 weeks of gestation for maternal dysglycemia in "high-risk" women. Evidence to support the early identification and treatment of gestational diabetes mellitus (GDM) is, however, limited. We examined the prevalence, clinical characteristics, and pregnancy outcomes of high-risk women with GDM diagnosed at <24 weeks of gestation (early GDM) and those with pre-existing diabetes compared with GDM diagnosed at >= 24 weeks of gestation, in a large treated multiethnic cohort. RESEARCH DESIGN AND METHODS Outcomes from 4,873 women attending a university hospital antenatal diabetes clinic between 1991 and 2011 were examined. All were treated to standardized glycemic targets. Women were stratified as pre-existing diabetes (n = 65) or GDM diagnosed at <12 weeks of gestation (n = 68), at 12-23 weeks of gestation (n = 1,247), or at >= 24 weeks of gestation (n = 3,493). RESULTS Hypertensive disorders in pregnancy including pre-eclampsia, preterm delivery, cesarean section, and neonatal jaundice (all P < 0.001) were more prevalent in women with pre-existing diabetes and early GDM. Macrosomia (21.8% vs. 20.3%, P = 0.8), large for gestational age (39.6% vs. 32.8%, P = 0.4), and neonatal intensive care admission (38.5% vs. 39.7%, P = 0.9) in women in whom GDM was diagnosed at <12 weeks of gestation were comparable to rates seen in women with pre-existing diabetes. CONCLUSIONS Despite early testing and current best practice treatment, early GDM in high-risk women remains associated with poorer pregnancy outcomes. Outcomes for those in whom GDM was diagnosed at <12 weeks of gestation approximated those seen in pre-existing diabetes. These findings indicate the need for further studies to establish the efficacy of alternative management approaches to improve outcomes in these high-risk pregnancies.