Cervical mucus removal before embryo transfer in women undergoing in vitro fertilization/intracytoplasmic sperm injection: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE To appraise critically the published randomized controlled trials (RCTs) reporting on the effectiveness of cervical mucus removal before embryo transfer. DESIGN Systematic review and meta-analysis of RCTs. SETTING Assisted reproduction technology (ART) units. PATIENT(S) Women undergoing embryo transfer after in vitro fertilization/intracytoplasmic sperm injection (IVF-ICSI). INTERVENTION(S) Cervical mucus removal followed or not by cervical irrigation immediately before embryo transfer. MAIN OUTCOME MEASURE(S) Clinical pregnancy, implantation and live-birth rates. RESULT(S) Eight RCTs involving 1,715 women were systematically analyzed. There was substantial heterogeneity among the included trials. There was no statistically significant difference in terms of pregnancy, implantation, or live-birth rates. CONCLUSION(S) A meta-analysis from the available moderate to low quality trials provides very little evidence of an overall benefit of cervical mucus removal before embryo transfer for women undergoing IVF/ICSI. Due to problems of clinical diversity, statistical heterogeneity, and risk of bias, additional pragmatic multicenter RCTs are needed to evaluate the possible small benefit of cervical mucus removal before embryo transfer.