Association between pre-gestational diabetes in women with polycystic ovary syndrome and adverse obstetric outcomes

Objective: To evaluate the effect of pregestational diabetes mellitus (DM) on the likelihood of experiencing adverse pregnancy, delivery, and neonatal outcomes in pregnant women with polycystic ovary syndrome (PCOS). Study design: A retrospective population-based study using data from the Healthcare Cost and Utilization Project Nationwide Inpatient Sample (HCUP-NIS) database was performed. All deliveries between 2004 and 2014, inclusively, were studied using ICD-9 codes. Within the study period, 14,882 women had a diagnosis of PCOS, of which 673 (4.7%) had a diagnosis of pregestational diabetes. Chi-squared tests were used for comparison of demographics. Multivariate logistic regression analysis was performed to calculate unadjusted and adjusted odds ratios (aORs) and corresponding 95% confidence intervals (CI), controlling for confounding effects. IRB approval was not required, given data was anonymous and publicly available. Results: Women with PCOS and pre-gestational DM were more likely to develop pregnancy complications, including pregnancy induced hypertension (aOR 1.55; CI 1.25-1.92), preeclampsia (aOR 1.45; CI 1.04-2.02), preeclampsia or eclampsia superimposed on pre-existing hypertension (aOR 1.85; CI 1.29-2.66), and placenta previa (aOR 2.53; CI 1.06-6.01), after controlling for confounding demographics. Women with PCOS who had pregestational diabetes were at increased risk of preterm delivery (aOR 1.40; CI 1.09-1.80), and delivery by cesarean section (aOR 1.50; CI 1.23-1.84). Results demonstrated no difference in the rate of women who gave birth to small for gestational age (SGA) infants, the rate of intrauterine fetal demises (IUFD), and the rate of infants with congenital anomalies between the two groups. Conclusion: The impact of pre-existing DM on the relationship between PCOS and pregnancy outcomes should be considered when counselling and planning care for pregnant women affected by these conditions. This emphasizes the importance of optimal perinatal care in diabetic women with PCOS as they are at higher risk of obstetric complications.