O-149 The Endometriosis Longitudinal Fertility Study (ELFS): Outcomes for women with moderate or severe endometriosis who are trying to conceive
Authors: Ross V , Mooney S , Dior U , Reddington C , Cheng C , Amir M , Harlow K , Stern C , Rogers P , Healey M 
Published: July 2024

Study question

What are the pregnancy outcomes for women with moderate or severe endometriosis who are trying to conceive?

Summary answer

Preliminary pregnancy rates in women with moderate/severe endometriosis are 11% for natural conception cycles and 22% for ART cycles. This is consistent with previous literature.

What is known already

Endometriosis is associated with reduced pregnancy rates in women attempting both spontaneous and assisted conception. Monthly fecundity is approximately half that of women without endometriosis and reduces further with increasing severity of disease. At present, the effect of surgery on the fertility outcomes of women with moderate or severe endometriosis remains unanswered. Treatment decisions are complex, particularly in those without pain symptoms seeking to optimise fertility outcomes.

Study design, size, duration

ELFS is a prospective multi-site longitudinal cohort study being conducted over 5-years. This interim report summarises data from August 2021-January 2024 in participants &lt;38 years with evidence of in-situ moderate or severe endometriosis desiring fertility immediately or in the future. ELFS prospectively measures and compares monthly clinical pregnancy and live birth rates in women having either surgical or conservative management of endometriosis. This report assesses outcomes for those trying to conceive naturally or with ART.

Participants/materials, setting, methods

Following consent and baseline questionnaire completion, participants install the purpose-built ELFS App to their mobile phone or use a web-based option to complete cyclical surveys. The timing of surveys is dependent on a learned logic within the App and based on menstrual cycle length and pregnancy status. Participants report attempted conception cycles and any ART treatments undertaken with IVF or intrauterine insemination (IUI). Pregnancy outcomes are recorded as well as surgery during the study period.

Main results and the role of chance

There are 124 participants enrolled in ELFS, 86 (69%) are in the surgical cohort and 38 (31%) in the conservative cohort. There are 45 participants (36%) who have indicated they are actively trying to conceive during the study and a total of 171 cycles have been recorded from these participants. Of those trying to conceive, 24 (53%) have elected to have surgery during the study period, compared to 23 (29%) who were not trying to conceive. The study has captured 126 cycles with attempted conception. Of these, 42 cycles (33%) utilised ART compared to 84 cycles (67%) of natural conception attempts. Of the ART cycles, 27 (75%) involved IVF with fresh or frozen embryo transfer and there were 9 (15%) IUI cycles. To date, there are 25 reported pregnancies. The pregnancy rate for ART cycles was 22% (8/36) compared to 11% (9/87) in the natural conception cycles. Of those who conceived following surgery, 47% (8/17) of pregnancies were following ART and 53% (9/17) were natural conceptions. There are 2 live births recorded, both from the cohort who had surgery during the study. A total of 5 miscarriages (20%) have been reported, 4 (80%) from the surgical cohort.

Limitations, reasons for caution

In the absence of data to guide management in this area, clinician scope of practice and concurrent pain symptoms are likely to influence recommendations for ART or surgery in those trying to conceive with moderate or severe endometriosis.

Wider implications of the findings

This preliminary data is consistent with the current literature showing reduced natural and assisted conception rates in women with moderate or severe endometriosis. Long-term data will be required to determine if fertility and pregnancy outcomes are influenced by surgical management of endometriosis.

Trial registration number

ACTRN12621000431820 (ANZCTR)