In vitro fertilization is associated with an increased risk of borderline ovarian tumours

Abstract

Objectives: To compare the risk of borderline ovarian tumours in women having in vitro fertilization (IVF) with women diagnosed with infertility but not having IVF.

Methods: This was a whole-population cohort study of women aged 20-44 years seeking hospital infertility treatment or investigation in Western Australia in 1982-2002. Using Cox regression, we examined the effects of IVF treatment and potential confounders on the rate of borderline ovarian tumours. Potential confounders included parity, age, calendar year, socio-economic status, infertility diagnoses including pelvic inflammatory disorders and endometriosis and surgical procedures including hysterectomy and tubal ligation.

Results: Women undergoing IVF had an increased rate of borderline ovarian tumours with a hazard ratio (HR) of 2.46 (95% confidence interval [CI] 1.20-5.04). Unlike invasive epithelial ovarian cancer, neither birth (HR 0.89; 95% CI 0.43-1.88) nor hysterectomy (1.02; 0.24-4.37) nor sterilization (1.48; 0.63-3.48) appeared protective and the rate was not increased in women with a diagnosis of endometriosis (HR 0.31; 95% CI 0.04-2.29).

Conclusions: Women undergoing IVF treatment are at increased risk of being diagnosed with borderline ovarian tumours. Risk factors for borderline ovarian tumours appear different from those for invasive ovarian cancer.