Follicular flushing in patients with poor ovarian response: a systematic review and meta-analysis

A systematic literature review and meta-analysis was conducted to evaluate the effect of follicular flushing on clinical outcomes (primary outcome: mean number of cumulus-oocyte-complexes [COC]) in poor-response IVF patients). The bibliographic databases OvidMedline (includes Pubmed), Cochrane Library and Web of Science were searched electronically for randomized controlled trials (RCT) comparing follicular flushing with no flushing. Three RCT with a total of 210 patients could be included. The mean number of COC did not increase with flushing (weighted mean difference: -0.45 COC, 95% CI -1.14 to 0.25, I² = 70%; P = 0.21; three RCT, n = 210). Mean number of metaphase II oocytes and the proportion of randomized patients having at least one COC retrieved were no different between groups. No difference was observed between groups for mean number of embryos, the proportion of randomized patients achieving embryo transfer, clinical pregnancy and live birth rates. Procedure duration was significantly increased with flushing (P = 0.0006). A positive effect of flushing on any of the investigated outcomes could not be observed in the existing literature in patients with poor ovarian response. Flushing is unlikely to significantly increase the number of oocytes, and the routine use of follicular flushing should, therefore, be scrutinized.