Does laparoscopic excision of endometriotic ovarian cysts significantly affect ovarian reserve? Insights from IVF cycles

Background: Residual ovarian function after laparoscopic excision of endometriotic ovarian cysts is a major and still unsolved topic. Ultrasonographic evaluation of ovarian response to ovulation stimulation represents a simple yet poorly employed tool to assess residual ovarian function after surgery. Methods: Data from patients referred for IVF or ICSI between January 2001 and December 2002 were reviewed. Patients were included who previously underwent laparoscopic excision of a monolateral endometriotic ovarian cyst. The operated ovary and contralateral intact ovary were compared in terms of number of follicles with a mean diameter >15 mm at the time of hCG administration. Basal volume of the two ovaries before initiating stimulation was also compared. A paired Student's t-test was used to investigate differences between the two ovaries. Results: In total, 32 patients and 46 cycles were identified. The mean (+/-SD) number of follicles >15 mm was 4.2+/-2.5 in the control ovary and 2.0+/-1.5 in the previously operated ovary (P<0.001); this corresponded to a mean reduction of 53% (95% CI 35-72%) but did not seem to be related to the dimension of the excised ovarian cyst. The basal volume of the operated ovaries was also statistically significantly diminished, though this reduction was less relevant. Conclusions: Excision of endometriotic ovarian cysts is associated with a significant reduction in ovarian reserve. Further studies are required to clarify whether the damage is related to the surgical procedure or to the previous presence of a cyst.