Subtle Endometriosis and Unexplained Infertility

  • Paula Andrea de Albuquerque de Salles Navarro
  • Anderson Sanches de Melo
  • Rui Alberto FerrianiEmail author


Unexplained infertility (UI) is a diagnosis of exclusion for infertile couples; within an otherwise asymptomatic patient with a normal clinical examination and ultrasound evaluation revealing no pelvic pathology, UI may be associated with undiagnosed pelvic diseases. We may speculate whether UI is really unexplained or if there are undocumented subtle pathological pelvic conditions that might interfere with the processes involved in natural fertilization. Subtle endometriosis may be related to various mechanisms involved in the different stages of fertilization, embryo development, and implantation, and there is speculation about its role in cases of UI. There is no consensus about whether milder stages of endometriosis are a cause of infertility or merely an incidental finding in some patients with UI. Studies by our group and others have shown that even cases of milder disease may inhibit mechanisms involved in conception, such as follicular steroidogenesis and oocyte competence. There appears to be an increase in oxidative stress (OS) markers in both the follicular and peritoneal compartments of patients with endometriosis as well as a possible increase in enzyme expression in cumulus granulosa cells (CC) which may alter oocyte development.

Cases of UI, especially those experiencing a long duration of infertility, may be due to subtle endometriosis with possible alterations in the mechanisms of oocyte maturation and response, fertilization, as well as later embryonic implantation. Assisted reproduction is an effective treatment option that can overcome as of yet unidentified intrinsic disturbances in patients with subtle endometriosis and UI.


Endometriosis Mild endometriosis Oxidative stress Unexplained infertility Gene expression Oocyte quality Ovarian steroidogenesis 


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Copyright information

© Springer Science+Business Media, LLC 2015

Authors and Affiliations

  • Paula Andrea de Albuquerque de Salles Navarro
    • 1
  • Anderson Sanches de Melo
    • 1
  • Rui Alberto Ferriani
    • 1
    Email author
  1. 1.Department of Obstetrics and GynecologyUniversity of São PauloRibeirão PretoBrazil

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