Rate of Spontaneous Preterm Delivery Between Pregnant Women With and Without Gestational Diabetes

Objective The aim of this study is to compare the rate of spontaneous preterm delivery between gestational diabetes mellitus (GDM) and normal pregnancy. Pregnancy outcomes and associated risk factors for spontaneous preterm delivery were evaluated. Methods A retrospective cohort study was conducted on 120 GDM and 480 normal pregnant women. All women received GDM screening with 50-g glucose challenge test and 100-g oral glucose tolerance test at the first visit and repeated at 24-28 weeks. Data were retrieved from medical records and included baseline and obstetric characteristics, preterm risks, GDM risks, and pregnancy outcomes. Spontaneous preterm birth was defined as delivery before 37 completed weeks of gestation that had been preceded by spontaneous labor. Results GDM women were more likely to be ≥30 years (p=0.032) and have previous GDM (p=0.013). Incidence of overall preterm delivery was significantly higher in GDM women (17.5% vs. 8.5%, p=0.004), as well as the incidence of spontaneous preterm delivery (15.8% vs. 7.1%, p=0.004). GDM women had less gestational weight gain (p<0.001) and were less likely to have excessive weight gain (p=0.002). GDM women were more likely to deliver large for gestational age (LGA) (p=0.02) and macrosomic infants (p=0.027). Neonatal hypoglycemia was significantly more common among GDM women (p=0.013). Multivariate analysis showed that previous preterm birth and GDM independently increased the risk of spontaneous preterm delivery (adjusted OR: 2.56, 95% CI: 1.13-5.79, p=0.024, and adjusted OR: 2.15, 95% CI: 1.2-3.84, p = 0.010, respectively). Conclusion GDM and previous preterm birth significantly increased the risk of spontaneous preterm delivery. GDM also increased the risk of LGA, macrosomia, and neonatal hypoglycemia.