Oocyte cryopreservation for patients with endometriosis: where are we now? A systematic review

The ambiguity of current recommendations on the use of oocyte cryopreservation in patients with endometriosis reflects the lack of comprehensive studies evaluating its efficacy. This review seeks to summarize all available data on the outcomes of oocyte cryopreservation and subsequent IVF, while taking patient characteristics into account. The review protocol was registered in PROSPERO (CRD42023486774). The search of electronic databases identified 10 observational studies. Due to their heterogeneity, the extracted data were only analysed descriptively. In terms of oocyte cryopreservation outcomes, the included studies consistently reported a decrease in the total number of oocytes retrieved as the age at cryopreservation increased and in cases of previous surgery for endometriosis; furthermore, this figure did not seem to depend on the type of endometriosis, and laterality or size of ovarian endometriomas. The trend for the number of metaphase II oocytes retrieved was largely consistent with that of total oocytes retrieved, while the oocyte maturation rate did not appear to be affected by a history of surgery for endometriosis. Conversely, there was a substantial lack of adequate follow-up data on the use of cryopreserved oocytes. Until these data become available, it will not be possible to confirm, with scientific certainty, the effectiveness of preventive oocyte cryopreservation in all women with endometriosis.