A study of pregnancy after endometrial ablation using linked population data.

INTRODUCTION Endometrial ablation encapsulates a range of procedures undertaken to destroy the endometrial lining of the uterus as a treatment for heavy menstrual bleeding in women who no longer wish to bear children. Pregnancy following ablation, whilst unlikely, can occur and may carry higher rates of complications. The aim of this study was to identify factors associated with post endometrial ablation pregnancy and to describe pregnancy and birth outcomes for post endometrial ablation pregnancies. MATERIAL AND METHODS This population-based data linkage study included all female residents of New South Wales, Australia aged 15-50 years with a hospital admission between July 2001 to June 2014, and who birthed between July 2001 to June 2015. Cox proportional hazard regression was used to estimate associations between women's characteristics and post endometrial ablation pregnancy of at least 20 weeks gestation. Descriptive statistics were used to characterize pregnancy and birth outcomes. RESULTS Of 18,559 women with an endometrial ablation, 575 (3.1%) women had a post ablation pregnancy of at least 20 weeks gestation. Nulliparity (adjusted hazard ratio (aHR) 12.2, 95% CI 9.1-16.2), older age [35-39 years (aHR 0.39, 95% CI 0.29-0.51), 40-44 years (aHR 0.06, 95% CI 0.04-0.11)], marital status [single (aHR 0.67, 95% CI 0.55-0.83), widowed/divorced/separated (aHR 0.58, 95% CI 0.36-0.94)] and a diagnosis of heavy menstrual bleeding (aHR 0.09, 95% CI 0.07-0.13) were associated with post ablation pregnancy. There were high rates of cesarean delivery (43%), preterm birth (13%), twin or higher order pregnancies (9%) and stillbirth (13.3/1000 births) among these post ablation pregnancies. CONCLUSIONS Nulliparity at the time of endometrial ablation is associated with increased risk of post ablation pregnancy, highlighting the importance of careful discussion and consideration of treatment options for heavy menstrual bleeding.