Whether endometriosis causes infertility or not is one of the most controversial issues in gynaecology. Opinions are divided regarding minimal-mild endometriosis. It is certainly the case that mild-minimal endometriosis is commonly found in women who have difficulty in conceiving.  The figure is as high as 70% in some studies.

It is however, generally accepted that severe disease does cause infertility due to the distortion of pelvic anatomy.  If the fallopian tubes are densely adherent to the ovaries they cannot pick up the eggs, nor can an egg be released from an ovary containing large, chocolate cysts. 

  • Possible causes of infertility in endometriosis
    Infertility may be due to poor ovarian function. There may be failure to ovulate, although this is quite a common problem whether a woman has endometriosis or not. In some women affected ovarian follicles may not grow at the normal rate. If the follicle develops normally the egg may not be released or the egg may not be normal.
  • Sperm or egg transport may be affected.  Muscular contractions of the fallopian tube help the egg/embryo to move along its length.  Chemical such as prostaglandins produced by endometriotic tissue influence their strength.  Altered tubal transport of eggs/embryos could cause infertility. Endometriosis causes an inflammatory reaction.  There are therefore, increased numbers of cell in the genital tract called macrophages, which attack sperm and reduce their survival time in the body.

    Implantation may be a problem caused by the endometrial dysfunction.

  • Treatment of infertility

    Suppression of ovarian function to improve fertility in minimal-mild endometriosis is not effective and should not be offered for this indication alone. There is no evidence of its effectiveness in more severe disease.

    Surgical removal of endometriotic lesions plus division of adhesions to improve fertility in minimal-mild endometriosis is effective compared to diagnostic laparoscopy alone.

    When endometriosis causes mechanical distortion of the pelvis, surgery should be performed if reconstruction of normal pelvic anatomy can be achieved.  The role of surgery in improving pregnancy rates for moderate-severe disease is uncertain

    Laparoscopic removal of cysts for ovarian endometriomas larger than 4 cm diameter improves fertility compared to drainage and coagulation. Coagulation or laser vaporization of endometriosis without removal of the whole cyst may result in recurrent cysts. The advantage of surgically treating a cyst before IVF or IUI is the acquisition of a histological diagnosis. A disadvantage is the loss of ovarian tissue containing follicles close to the cyst.

    Post-operative treatment
    Postoperative medical treatment prevents pregnancy and should be avoided in the first 6 to 12 months after conservative surgery in women who want to become pregnant.

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