The (Cost-)Effectiveness of Surgical Excision of Colorectal Endometriosis Compared to ART Treatment Trajectory

Inclusion Criteria: * Colorectal endometriosis defined as endometriosis involving the (colo)rectum: #Enzian classification score C1,C2,C3 (C=rectum) or FI (F=far locations, I=sigmoid colon) detected with ultrasound or MRI; * Women in a heterosexual or in a same-sex relationship; * The patient has an active wish to conceive and experiences at least one of the following criteria: * At least one year of non-conception (either spontaneous of after intra uterine inseminations) * Inability to have timed intercourse because of pain (dyspareunia and/or chronic pelvic pain) * Severe complaints (expectant management is not acceptable (anymore) * The patients has an indication for IVF/ICSI according to Dutch guidelines (Werkgroep netwerkrichtlijn, december 2010); * failed intra uterine insemination * male factor subfertility (oligoasthenoteratozoospermia defined as VCM \<1 million) * bilateral tubal pathology (e.g. bilateral hydrosalpinx, bilateral tubal occlusion) * age \> 38 years and (unexplained) subfertility * severe endometriosis in case of subfertility * The patient is faces the choice between IVF/ICSI or laparoscopic (colorectal) endometriosis or is on the waiting list for a respective treatment at T=0 (at the beginning of the treatment trajectory), T=1 (after one unsuccessful IVF/ICSI cycle) or T=2 (after 2 unsuccessful IVF/ICSI cycles) Exclusion Criteria: * Patients with deep endometriosis without colorectal involvement; * Patients who conceive spontaneously prior to intervention; * Patients requiring surgery on short notice and therefore unable to opt for IVF/ICSI (e.g. in case of unilateral or bilateral hydronephrosis, severe bowel stenosis and suspicion of an impending ileus); * Patients with a contra-indication for IVF/ICSI (e.g. diminished ovarian reserve (premature ovarian failure) (AMH (when available) \<p10 adjusted for age), untreated congenital uterine abnormalities, maltreated/untreated systemic or malignant disease or severe risk factors for oocyte aspiration); * Patients diagnosed with other diseases causing infertility (e.g. recurrent miscarriages, antiphospholipid syndrome); * Not able to read and understand Dutch or English.