476: Hyperglycemia and adverse pregnancy outcomes in twins: do the HAPO findings apply to twin pregnancies?

Abstract

In 2008, the HAPO study demonstrated in singleton pregnancies that maternal hyperglycemia, even less severe than in diabetes, was associated with adverse pregnancy outcomes. Our objective was to determine if hyperglycemia in twin pregnancies without gestational diabetes mellitus (GDM) is associated with an increased risk of adverse pregnancy outcomes. Retrospective cohort study of twin pregnancies in a single MFM practice between 2005 and 2019 who underwent two-step GDM screening at 24-28 weeks. We excluded women with pregestational or gestational diabetes. We examined the association between maternal glycemia and adverse pregnancy outcomes. Glycemia was defined as the 1-hour GCT in all women, and each of the four values of the 3-hour GTT in women who failed the GCT (≥130 mg/dL). Primary outcomes were preeclampsia, cesarean delivery, and neonatal hypoglycemia in either twin. Statistical tests used included Pearson correlation, Student’s t-test, chi-square for trend, and linear regression. 847 women underwent a GCT and 246 women underwent a GTT. Increasing maternal glucose levels had no positive association with adverse outcomes. Women with preeclampsia, cesarean delivery, and neonatal hypoglycemia did not have higher mean GCT or GTT values than women without these outcomes. On Pearson correlation, none of the GCT or GTT values were associated with adverse outcomes, aside from a negative correlation between the fasting GTT value and neonatal hypoglycemia. There was no increased risk of adverse outcomes with increasing quartiles of the GCT or GTT values (figure). Increasing fasting GTT was negatively associated with neonatal hypoglycemia. In women with twin pregnancies without GDM, increasing maternal glucose levels are not associated with adverse outcomes. In contrast, increased maternal glucose values may be associated with a decreased risk of neonatal hypoglycemia. This suggests that the diagnosis and treatment of GDM in twin pregnancies need to be revisited, as the recommendations come from data in singleton pregnancies which may not be applicable to twins.