What are the effects of different endometriosis treatments on pregnancy outcomes?

A gynecologist communicates with her patient, indicating the menstrual cycle on the monitor.

Affecting approximately a million people in Canada, endometriosis is a chronic condition in which endometrial-like tissue grows outside the uterus. Just like endometrial tissue, this tissue breaks down with every menstrual cycle, often resulting in inflammation, pain and scarring which affects the reproductive organs and can lead to infertility. There is no cure for endometriosis, but its symptoms may be treated with medicines or, in some cases, surgery.

University of British Columbia Faculty of Medicine PhD candidate, Jalisa Karim, has received approval to access data for a population-based research project to examine endometriosis treatments and pregnancy outcomes. The project is being supervised by Professor Gillian Hanley, and is funded by the Canadian Institutes of Health Research (CIHR).

According to Ms. Karim, a recent systematic review and meta-analysis of research to date found higher risks for endometriosis patients compared with patients without endometriosis on numerous adverse pregnancy outcomes, including gestational hypertension, pre-eclampsia, preterm birth, placenta previa, placental abruption, caesarean section, and stillbirth.

“Due to the high rates of infertility among patients with endometriosis, many turn to assisted reproductive technologies,” says Ms. Karim. “However, researchers have found a possible association between endometriosis and adverse fetal outcomes with assisted reproduction, and there remains a need to better understand reproductive outcomes among people with endometriosis who have received a variety of treatments, including rates of adverse events in pregnancies arising among patients who had previously been treated for endometriosis.”

The project will build a population-based cohort including all females living in British Columbia between 2000 and 2021, with data beginning in 1995 to understand the surgeries and treatments received five years prior to cohort entry. PopData will link eight data sets from the BC Ministry of Health with data from the BC Perinatal Data Registry.

In order to carry out the research, the team will build and validate an algorithm to most sensitively and specifically identify endometriosis patients in the administrative data. For that they will use a separate Vancouver Coastal Health data set of pathologically confirmed endometriosis patients created by a team of gynaecologic oncologists, pathologists, and researchers at Vancouver General Hospital. The data set has already been linked with the population-based administrative data sets, with data linkage performed by PopData.