Reconsidering IVF/ICSI outcomes in endometriosis: phenotype variability, confounding factors, and clinical interpretation

Abstract Background Endometriosis is a biologically heterogeneous disorder frequently encountered in women undergoing assisted reproductive technology (ART). Reported effects on in vitro fertilization and intracytoplasmic sperm injection (IVF/ICSI) outcomes remain inconsistent across studies, partly due to variations in disease phenotype, prior surgical treatment, ovarian reserve, and concomitant uterine pathology. Objective To critically evaluate contemporary evidence regarding IVF/ICSI outcomes in women with endometriosis, with emphasis on phenotype-related reproductive variability, sources of evidence heterogeneity, and implications for individualized reproductive management. Methods A structured narrative review was performed using PubMed/MEDLINE, Embase, and Scopus databases. Literature published between January 2015 and March 2026 was screened, with particular focus on contemporary studies evaluating ovarian response, embryological parameters, implantation, live birth, cumulative reproductive outcomes, and the potential confounding role of adenomyosis. Results Current evidence suggests that the reproductive impact of endometriosis is not uniform across patient populations. Ovarian endometrioma and previous ovarian surgery are most consistently associated with reduced ovarian reserve and lower oocyte yield, whereas superficial peritoneal disease appears to exert less pronounced effects on ovarian responsiveness. Embryological outcomes are frequently preserved despite impaired ovarian response, although substantial heterogeneity exists among studies. Implantation and live birth outcomes may additionally be influenced by uterine factors, particularly adenomyosis, which may independently impair reproductive efficiency. Differences in study design, patient selection, disease classification, and outcome reporting contribute significantly to variability in the available literature. Conclusions IVF/ICSI prognosis in women with endometriosis should be interpreted within a phenotype-specific and multifactorial clinical context rather than through a single generalized disease model. Contemporary evidence supports individualized reproductive assessment integrating ovarian reserve, surgical history, adenomyosis evaluation, and cumulative treatment trajectory when counselling and managing women with endometriosis undergoing ART.