O-250 Infertility and endometriosis: a 30-yearlong national population-based study of prevalence, association and pregnancy outcomes

Abstract

Study question What is the population prevalence of endometriosis in those with infertility (and vice-versa) and likelihood of pregnancy in women with endometriosis with and without infertility? Summary answer Women with endometriosis associated infertility are 2.5 times more likely to have a pregnancy compared with other causes of female infertility. What is known already While the link between endometriosis and infertility is well recognised, the true prevalence of endometriosis in women with infertility (and vice versa) is not clearly known. Most of the available data has been derived from hospital-based studies with relatively small sample size. Similarly, there is limited data on likelihood of pregnancy and their outcomes (such as live birth, miscarriage, ectopic) in individuals with endometriosis-associated infertility compared with other causes of infertility as well as overall chances of pregnancy in those with endometriosis – a key concern for women when they first receive the diagnosis of endometriosis. Study design, size, duration A population-based national cohort study using routinely collected linked data from primary and secondary care and maternity database. The study comprised of > 4million women with infertility and other symptoms of endometriosis (pelvic pain, dysmenorrhoea) in England over a period of 30 years (1991-2020). Participants/materials, setting, methods Routinely collected primary care data on 4,041,770 women aged 13-50 years with infertility and other endometriosis symptoms was linked with secondary care data (hospital data and maternity records) to identify those with surgically confirmed diagnosis of endometriosis to estimate prevalence. Data was collected on age, social class and year of diagnosis. Logistic regression was used to evaluate odds of pregnancy in women with endometriosis compared to other causes of infertility and in those without endometriosis. Main results and the role of chance Between 1991 and 2020, there were 4,041,770 women aged 13-50 years, who attended primary care with infertility (n = 245,994) or other symptoms of endometriosis (e.g. pelvic pain, dysmenorrhoea and dyspareunia). 111,197 women had a surgically confirmed diagnosis of endometriosis via laparoscopy or laparotomy during this period. The overall population prevalence (95% CI) of female infertility (per 1000 women) over a 30-year period was 48.9 (48.6, 49.0). with highest prevalence between 30-39 years. Amongst those with infertility, 6.1% (14,904) had surgically confirmed endometriosis, of which 57.4% (8,556) had infertility before their diagnosis of endometriosis. The chances of having endometriosis in women with infertility was 2.5 times higher compared to those without infertility with Odds ratio (OR) and 95% CI of 2.48 (2.43,2.52). Among women with infertility, 12.9% (31,821) had at least one pregnancy during the study period. The chances of having a pregnancy in those with endometriosis associated infertility was 2.5 times higher compared to other causes of female infertility with OR (95% CI) of 2.50 (2.46, 2.66). Of those diagnosed with endometriosis irrespective of associated infertility, 40.5% had at least one pregnancy. Data on primary/secondary care infertility and pregnancy outcome will be included in the conference presentation. Limitations, reasons for caution While the study is a true representation of population with infertility, endometriosis and their pregnancy rates, it cannot account for women with endometriosis who did not intend to have children versus unable to conceive. Undiagnosed endometriosis in the control group who have not had surgery cannot be excluded. Wider implications of the findings The large size and long duration of the study with population-based data provides a realistic burden of infertility and endometriosis in the population, that can be used for health services planning and to counsel women with a new diagnosis of endometriosis regarding chances of infertility, pregnancy and their outcomes. Trial registration number No