Infertility etiology, assisted reproduction, and occurrence of hypertensive disorders of pregnancy: a cohort study

OBJECTIVE: To assess whether hypertensive disorders of pregnancy (HDP) vary by underlying causes of infertility. STUDY DESIGN: Cohort study using Quebec provincial administrative health data (RAMQ, ISQ, MED-ÉCHO). METHODS: We compared 6273 pregnant women previously evaluated for infertility at an academic fertility clinic (exposed) with 10,810 pregnant women with no recent medical history of infertility (unexposed), who gave birth between 1996 and 2017. We used multivariable Poisson regression with robust error variance to estimate risk ratios and 95% confidence intervals by infertility status, type of fertility treatment (ART, non-ART, and untreated), and infertility diagnosis, adjusting for age, first language, education, birthplace, and period of conception. RESULTS: Compared with unexposed pregnancies, those resulting from any fertility treatment for male factor infertility, tubal disease, and ovulatory disorders showed a higher occurrence of HDP. Endometriosis was associated with a higher occurrence of HDP only in ART-treated pregnancies. ART was associated with higher occurrence of HDP across most infertility diagnoses. The association between ovulatory disorders and HDP persisted regardless of treatment or multiplicity, whereas, for tubal disease, the association varied by treatment type. CONCLUSIONS: Ovulatory disorders and tubal disease were associated with higher occurrence of HDP. ART was independently associated with HDP across most infertility diagnoses. The association between ovulatory disorders and HDP was independent of treatment, suggesting that underlying biological conditions, and not treatment alone, may be relevant to HDP risk.