Maternal and fetal outcomes among women with GDMA1 before and post-date

•The study investigated adverse pregnancy outcomes in women with GDMA1 who delivered at term before or post date.•1303 (11%) women with GDMA1 delivered at term post-date and 10,462 (89%) delivered at term before date.•No significant increase in adverse pregnancy outcomes at term post-date pregnancies complicated with GDMA1 was demonstrated.•There was no increase in the rate of Cesarean Deliveries with the increase in gestational age until 41 weeks of gestation. To investigate adverse pregnancy outcomes in patients complicated with GDMA1 who delivered at term before or after 40 weeks of gestation. A population-based cohort study including all women with GDMA1 during pregnancy was conducted. Deliveries occurred between 1988 and 2016 at a large university tertiary medical center. During the study period, 11,765 women with GDMA1 met the inclusion criteria. Of these, 1303 (11 %) delivered after 40 weeks (post-date, study group), while 10,462 (89 %) delivered at term before 40 weeks of gestation (before date, control group). Those who delivered after 40 weeks of gestation (the study group) had a significantly lower percent of cesarean deliveries (CD), higher rates of spontaneous vaginal deliveries and induction of labor in comparison to those who delivered before 40 weeks of gestation (the control group). The control group had significantly higher rates of preeclampsia and intrauterine growth restriction than the study group. Using a multivariable logistic regression model, delivery after 40 weeks was noted as an independent protective factor for CD (adjusted OR = 0.78, 95 %CI 0.66–0.92, p value = 0.001). Delivery after 41 + 0 weeks had a significantly higher rate of CD and LGA. No significant increase in adverse pregnancy outcomes at term post-date pregnancies complicated with GDMA1 was demonstrated. Furthermore, there was no increase in the rate of CD with the increase in gestational age until 41 weeks of gestation.