Comparison of pregnancy outcomes between women with early‐onset and late‐onset gestational diabetes in a retrospective multi‐institutional study in Japan

AIMS/INTRODUCTION: To compare pregnancy outcomes between women with gestational diabetes mellitus (GDM) diagnosed early and late in pregnancy in Japan. MATERIALS AND METHODS: We examined women diagnosed with GDM in this multi-institutional retrospective study. Women were divided into two groups by gestational age at diagnosis: <24 weeks of gestation (early group, 14.4 ± 4.2 weeks) and ≥24 weeks of gestation (late group, 29.6 ± 3.4 weeks). Dietary counseling with self-monitoring of blood glucose with or without insulin therapy was initiated for both groups. Pregnancy outcomes were compared between the groups. RESULTS: Data from 600 early and 881 late group participants from 40 institutions were included. Although pre-pregnancy body mass index was higher in the early group than in the late group, gestational weight gain was lower in the early group. Hypertensive disorders of pregnancy and cesarean section were more prevalent in the early than in the late group (9.3% vs 4.8%, P < 0.001; 34.2% vs 32.0%, P < 0.001, respectively). The prevalence of large-for-gestational-age infants was higher in the late than in the early group (24.6% vs 19.7%, respectively, P = 0.025). There was no significant difference in other neonatal adverse outcomes between the groups. Multiple logistic regression analysis showed that early group, nulliparity and pre-pregnancy body mass index were associated with hypertensive disorders of pregnancy. CONCLUSIONS: These results suggest that maternal complications, including hypertensive disorders of pregnancy and cesarean delivery, were higher in the early group than in the late group. Earlier intervention for GDM might be associated with a reduction in large-for-gestational-age infants.