Relationship between Polycystic Ovarian Syndrome and Subsequent Gestational Diabetes Mellitus: A Nationwide Population-Based Study

OBJECTIVE: This nationwide population-based study aims to explore the relationship between polycystic ovarian syndrome (PCOS) and subsequent gestational diabetes mellitus (GDM). METHODS: Data from 1998–2012 Taiwan National Health Insurance Research Database were used for this study. ICD9-CM codes 256.4X and 648.X were used separately for the diagnoses of PCOS and GDM, which were further confirmed by records of blood tests or ultrasonography to ensure the accuracy of the diagnoses. Women diagnosed at < 15 or > 45 years of age, and those diagnosed with overt diabetes mellitus or GDM prior to PCOS were excluded. During pregnancy, each woman with a previous diagnosis of PCOS was age-matched to 10 women without PCOS. Odds ratios (ORs) for risk of GDM were calculated by logistic regression analysis with adjustment for economic status and co-morbidities. RESULTS: Among 7,629 eligible women with a valid PCOS diagnosis, 3,109 (42.87%) had subsequent pregnancies. GDM occurred frequently among women with a history of PCOS as compared to those without PCOS (20.46% vs. 10.54%, p<0.0001). Logistic regression analysis revealed that PCOS was associated with GDM (adjusted OR = 2.15; 95% CI:1.96–2.37). Among 3,109 affected patients, 1,160 (37.31%) had used medications for PCOS and 261 (8.39%) were treated with an oral hypoglycemic agent (OHA). There was no significant difference in development of GDM between the medication and no medication sub-groups (p>0.05). If not used after conception, OHAs did not reduce the risk of GDM (adjusted OR = 1.20; 95% CI:0.88–1.62). CONCLUSIONS: A history of PCOS is a significant and independent risk factor for development of GDM. Medication for PCOS or pre-pregnancy use of OHAs does not reduce the risk of GDM. When at-risk women become pregnant, they require closer surveillance for maternal and fetal well-being, and should follow a strict diet and adhere to weight gain control to avoid obstetric complications due to GDM.