When severe endometriosis occurs in women with infertility, the ovaries may contain fluid‐filled spaces called endometriomas (“chocolate cysts”) on pelvic ultrasound. Endometriomas can be found on the left, right, or both ovaries simultaneously (bilateral). Traditionally, surgery was recommended to remove these cystic lesions prior to IVF. More recently, doctors are concerned that such surgery may significantly reduce the number of available eggs in the ovaries without improving fertility overall or the outcome of a subsequent IVF cycle.
Because of this worry, medical investigators in Madrid, Spain, recently studied the IVF outcome in asymptomatic women with unoperated bilateral endometriomas. 78 women who had no history or evidence of endometriosis acted as the control group. The study found that the response of the ovaries to fertility medications was reduced in women with bilateral endometriomas. This means fewer eggs were collected. However, the rate of fertilization of the eggs and the implantation rates were not affected. Similarly, the number of pregnancies and deliveries did not differ between the affected women with endometriosis and the unaffected control group. Therefore, although the presence of endometriomas in women planning IVF appears to reduce the number of oocytes retrieved, the chance of pregnancy is not affected. An endometriotic ovarian cyst observed on ultrasound prior to IVF does not mean that surgery is needed.