Pregnancy and Childbirth Outcomes of Gestational Diabetes Mellitus: A Retrospective Cohort Study

Background: Understanding the various outcomes of gestational diabetes mellitus (GDM) is essential for initiating a cascade of preparatory steps to address them. Therefore, we aimed to evaluate the pregnancy and childbirth outcomes of GDM. Methods: : We retrospectively assessed singleton pregnant mothers diagnosed with GDM who gave birth at Khaleej-e-Fars Hospital (a tertiary hospital) in Bandar Abbas, Iran, between January 1st, 2020, and January 1st, 2022. Records of women with pre-existing diabetes mellitus, chronic hypertension, cardiovascular disease, thyroid dysfunction, preeclampsia, abnormal placentation (previa or acreta), severe anemia (hemoglobin≤7), infertility, and COVID-19 at the time of admission were excluded. Pregnancy and childbirth outcomes included the incidence of the need for induction of labor, placenta abruption, preterm birth, intrauterine growth restriction (IUGR), intrauterine fetal death (IUFD), meconium fluid, fetal distress, methods of delivery, perineal lacerations, postpartum hemorrhage, childbirth injury, shoulder dystocia, macrosomia, low birth weight, congenital malformation, neonatal asphyxia, need for cardiac, respiratory resuscitation, transfer to neonatal intensive care unit (NICU), and newborn death. Results: : The records of 7748 eligible mothers were included in the analysis. GDM was diagnosed in 1087 (14%) of mothers. Age was the only sociodemographic factor that differed significantly between GDM and non-GDM mothers. The Chi-square test result revealed that macrosomia, labor induction, instrumental deliveries, NICU admissions, and IUFD were more common in GDM mothers, while the incidence of CS, meconium fluid, and IUGR were less common in GDM mothers. The impact of GDM on adverse events of pregnancy and childbirth was evaluated using logistic regression analysis. GDM mothers had a significantly higher risk of macrosomia (aOR: 2.94, 95%CI: 1.71–4.61), labor induction (aOR: 3.14, 95%CI: 1.72–6.95), instrumental delivery (aOR: 3.16, 95%CI: 1.51–3.87), IUFD (aOR: 1.95, 95%CI: 1.17–3.06), and NICU admission (aOR: 2.19, 95%CI: 0.99–3.82). Other common complications, such as CS, postpartum hemorrhage, shoulder dystocia, childbirth trauma, and extensive perineal lacerations, were not significantly different between GDM and non-GDM mothers. Conclusions: : Despite the higher incidence of labor induction and instrumental delivery, we found no significant association between GDM and adverse maternal outcomes. Regarding neonatal outcomes, GDM was linked to macrosomia, IUFD, and NICU admission.