Pregnancy outcome in pregnancies complicated with gestational diabetes mellitus and late preterm birth

Aim: To assess pregnancy outcome among women with gestational diabetes mellitus (GDM) delivering at the late preterm period. Methods: Retrospective observational cohort of all women with GDM who delivered a singleton fetus at the late preterm birth period (34 + 0/7 to 36 + 6/7 weeks of gestation). The study group included all women diagnosed with GDM and were compared to a control group of women delivering at the same gestational age period but without known GDM. Results: 1849 women were included in the study, of whom 132 (7.1%) were diagnosed with GDM and 1717 (92.9%) were not. Women with GDM had a lower rate of spontaneous vaginal delivery (45.5% vs. 62.9%, p < 0.001) and a higher rate of cesarean delivery (50.8% vs. 31.8%, p < 0.001). GDM diagnosis incurs an adjusted ratio of 1.82 for cesarean delivery (95% CI 1.24-2.66, p = 0.002). Neonates of mothers with GDM had significant higher mean birth weight and birth weight percentile, including higher rate of large-for-gestational age newborns. There were no differences in mortality or other parameters for neonatal morbidity. Conclusion: according to our data, late preterm occurring in women with GDM does not confer an increased risk for neonatal complications.