Treatment of mild gestational diabetes did not prevent neonatal complications but reduced fetal overgrowth

Randomized controlled trial. ClinicalTrials.gov NCT00069576.

Concealed.*

Partially blinded (931 women without GDM were included in the usual care group to mask the status of women randomized to that group).*

To delivery.

14 university hospitals in the USA (Maternal–Fetal Medicine Units Network).

958 women (mean age 29 y, 24% primigravida) with a singleton pregnancy who had blood glucose 7.5 to 11.1 mmol/L (135 to 200 mg/dL) 1 hour after a 50-g glucose-loading test at 24 to < 31 weeks’ gestation. Exclusion criteria included preexisting diabetes or previous GDM, abnormal glucose test at < 24 weeks, and expected preterm delivery. Eligible women were included if a 3-hour 100-g oral glucose tolerance test showed mild GDM (fasting glucose < 5.3 mmol/L [95 mg/dL] and ≥ 2 of 1-hour glucose > 10.0 mmol/L [180 mg/dL], 2-hour glucose > 8.6 mmol/L ([155 mg/dL], or 3-hour glucose > 7.8 mmol/L [140 mg/dL]).

Nutritional counseling and diet therapy, daily self-monitoring of blood glucose, and insulin treatment if fasting glucose ≥ 5.3 mmol/L or 2-hour postprandial glucose ≥ 6.7 mmol/L (120 mg/dL) (n = 485); or usual prenatal care (n = 473). In the control group, if there was suspicion of hyperglycemia, glucose testing could be done and treatment started if random blood glucose was ≥ 8.9 mmol/L (160 mg/dL) or fasting glucose was ≥ 5.3 mmol/L.

Primary composite endpoint (perinatal death; neonatal hypoglycemia, hyperbilirubinemia, or hyperinsulinemia; or birth trauma), birthweight, macrosomia (birthweight > 4000 g), large for gestational age (birthweight > 90th percentile), cesarean delivery, shoulder dystocia, preeclampsia, and maternal weight gain.

94% (intention-to-treat analysis).

Groups did not differ for the composite endpoint or any of its components (no perinatal death in either group) (Table). Treatment of GDM reduced risk for several maternal and neonatal outcomes (Table). Mean birthweight was lower (3302 g vs 3408 g, P < 0.001) and mean maternal weight gain was less (2.8 vs 5.0 kg, P <0.001) in the treatment group.

In women with mild gestational diabetes, treatment involving diet and insulin, if necessary, did not affect risk for a composite of perinatal death and neonatal complications but reduced fetal overgrowth and obstetric complications.