The impact of endometriosis on the outcome of Assisted Reproductive Technology

BACKGROUND Endometriosis has been described to impair fertility through various mechanisms. However, studies evaluating the reproductive outcomes of women undergoing assisted reproductive technologies show controversial results. The aim of this study is to assess whether the reproductive outcome is impaired among women with endometriosis-associated infertility undergoing IVF. METHODS A retrospective cohort study was performed, including women undergoing IVF reported by the Red Latinoamericana de Reproduccion Asistida (Redlara) registry, between January 2010 and December 2012. The study group included women with endometriosis-associated infertility, and the control group women with tubal factor, endocrine disorders or unexplained infertility. Women above 40 years, severe male factor and premature ovarian failure were excluded. The reproductive outcomes of between both groups were compared. The primary outcome was live birth. Secondary outcomes included clinical pregnancy, miscarriage, number of oocytes retrieved and number of fertilized oocytes. Outcomes were assessed after the first fresh IVF cycle, and were adjusted for age and number of embryos transferred. RESULTS A total of 22.416 women were included (3.583 with endometriosis and 18.833 in the control group). Mean age of patients in the endometriosis group and control group was 34.86 (3.47) and 34.61 (3.91) respectively, p = 0.000. The mean number of oocytes retrieved were 8.89 (6.23) and 9.86 (7.02) respectively, p = 0.000. No significant differences were observed between groups in terms of live birth (odds ratio (OR) 1.032, p = 0.556), clinical pregnancy (OR 1.044, p = 0.428) and miscarriage rates (OR 1.049, p = 0.623). Women with endometriosis had significantly lower number of oocytes retrieved (incidence risk ratio (IRR) 0.917, 95% CI 0.895-0.940), however, the number of fertilized oocytes did not differ among the two groups when adjusting for the number of oocytes retrieved (IRR 1.003, p = 0.794). An age-stratified analysis was performed, and no differences were observed in the reproductive outcomes between groups for women aged under 35 and 35 to 40. CONCLUSIONS Reproductive outcomes among women undergoing IVF and diagnosed with endometriosis-associated infertility do not differ significantly from women without the disease. Although women with endometriosis generate fewer oocytes, fertilization rate is not impaired and the likelihood of achieving a live birth is also not affected.