Prevalence of gestational diabetes and its association with stillbirth, preterm birth, macrosomia, abortion and cesarean delivery: a national prevalence study of 11 provinces in Iran

Background: Gestational diabetes mellitus (GDM) is one of the most common metabolic disorders during pregnancy that significantly affects perinatal outcomes. Objective: The aim of this study was to determine the prevalence of GDM and its relation with the incidence of stillbirth, preterm birth, macrosomia, abortion and cesarean section (C-section) delivery in pregnant women. Methods: This cross-sectional study was conducted on 3675 pregnant women in 11 provinces across Iran. Cluster sampling was used to select samples from mothers covered by health plans in 11 provinces of Iran. Prevalence of adverse pregnancy outcomes, including preterm delivery, type of delivery, macrosomic preterm birth, miscarriage, stillbirth, infant death, and birth weight were measured, using family record and face-to-face interviews. Data were analyzed by logistic regression, using STATA14.2 software. Results: About four percent of Iranian pregnant women had GDM during pregnancy. Prevalence of C-section was significantly higher in diabetic women than in the non-diabetic ones (53.19 vs 46.81, respectively, P < 0.001). Abortion in diabetic mothers was more than twice that of the non-diabetic mothers (P < 0.001). In the adjusted logistic regression model, the odds of stillbirth in mothers with GDM were 1.8 (95% CI: 1.11, 2.91, P = 0.018) times higher than that of the non-diabetics. The odds of macrosomia in diabetic women was about 7 times higher than the non-diabetic women (95% CI: 2.81, 17.14, P < 0.001). The odds of GDM had an increasing trend according to the BMI (p < 0.001). The risk of GDM were significantly lower, according to the daily physical activity (PA) (p < 0.001). Conclusion: The GDM prevalence has a decreasing trend in Iran. It increases the adverse pregnancy outcomes such as stillbirth, neonatal deaths, macrosomia, preterm birth, abortion and C-section delivery. As, some of these consequences like macrosomia are not treatable, thus early prevention is very crucial.