Long‐term GnRH agonist therapy before in vitro fertilisation (IVF) for improving fertility outcomes in women with endometriosis

Background Endometriosis is known to have an impact on fertility and it is common for women affected by endometriosis to require fertility treatments, including in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI), to improve the chance of pregnancy. It has been postulated that long‐term gonadotrophin‐releasing hormone (GnRH) agonist therapy prior to IVF or ICSI can improve pregnancy outcomes. This systematic review supersedes the previous Cochrane Review on this topic (Sallam 2006). Objectives To determine the effectiveness and safety of long‐term gonadotrophin‐releasing hormone (GnRH) agonist therapy (minimum 3 months) versus no pretreatment or other pretreatment modalities, such as long‐term continuous combined oral contraception (COC) or surgical therapy of endometrioma, before standard in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) in women with endometriosis. Search methods We searched the following electronic databases from their inception to 8 January 2019: Cochrane Gynaecology and Fertility Specialised Register of Controlled Trials, CENTRAL via the Cochrane CENTRAL Register of Studies ONLINE (CRSO), MEDLINE, Embase, PsycINFO, Cumulative Index to Nursing and Allied Health Literature (CINAHL). We searched trial registries to identify unpublished and ongoing trials. We also searched DARE (Database of s of Reviews of Effects), Web of Knowledge, OpenGrey, Latin American and Caribbean Health Science Information Database (LILACS), PubMed, Google and reference lists from relevant papers for any other relevant trials. Selection criteria Randomised controlled trials (RCTs) involving women with surgically diagnosed endometriosis that compared use of any type of GnRH agonist for at least three months before an IVF/ICSI protocol to no pretreatment or other pretreatment modalities, specifically use of long‐term continuous COC (minimum of 6 weeks) or surgical excision of endometrioma within six months prior to standard IVF/ICSI. The primary outcomes were live birth rate and complication rate per woman randomised. Data collection and analysis Two independent review authors assessed studies against the inclusion criteria, extracted data and assessed risk of bias. A third review author was consulted, if required. We contacted the study authors, as required. We analysed dichotomous outcomes using Mantel‐Haenszel risk ratios (RRs), 95% confidence intervals (CIs) and a fixed‐effect model. For small numbers of events, we used