Introduction: A randomized multicenter study was conducted in the Stockholm-orebro areas in Sweden to evaluate how treatment aiming at normoglycemia affects fetal growth, pregnancy and neonatal outcome in pregnant women with severe hyperglycemia.

Material and methods: Pregnant women with hyperglycemia defined as fasting capillary plasma glucose <7.0 mmol/L and a two-hour plasma glucose value 10.0 and <12.2 mmol/L following a 75-g oral glucose tolerance test (OGTT) diagnosed before 34 weeks of gestation were randomized to treatment (n=33) or controls (n=36). Women assigned to the control group were blinded for the OGTT results and received routine care. The therapeutic goal was fasting plasma glucose 4-5 mmol/L, and <6.5 mmol/L after a meal. Primary outcomes were size at birth and number of large-for-gestational age (>90th percentile) neonates. Secondary outcomes were pregnancy complications, neonatal morbidity and glycemic control.

Results: The planned number of participating women was not reached. There was a significantly reduced rate of large-for-gestational age neonates, 21 vs. 47%, P<0.05. Group differences in pregnancy complications and neonatal morbidity were not detected because of limited statistical power. In total, 66.7% of the women in the intervention group received insulin. Of all measured plasma glucose values, 64.1% were in the target range, 7.2% in the hypoglycemic range and 28.7% above target values. There were no cases of severe hypoglycemia.

Conclusions: Aiming for normalized glycemia in a pregnancy complicated by severe hyperglycemia reduces fetal growth but is associated with an increased rate of mild hypoglycemia.