Systematic review analyzing significance of endometrial cavity fluid during assisted reproductive techniques.

OBJECTIVE: The objective of our study is to estimate the prevalence of endometrial cavity fluid (ECF) in Assisted Reproductive Techniques (ART) cycles and analyze its effects on pregnancy outcome in such cycles. DATA SOURCES: PubMed, Cochrane Central, Scopus, and clinicaltrials.gov were searched for articles. The reference lists of relevant publications were explored for other studies. STUDY ELIGIBILITY CRITERIA: Studies that had assessed the pregnancy outcome in ART cycles and had commented on ECF accumulation were included. Pregnancy outcomes were assessed in all ART cycles where ECF was observed and were compared to the non-ECF cycles. RESULTS: A total of nine studies were included in the meta-analysis for a total of 28,210 cycles. Pooled analysis of the prevalence of ECF cycles out of total cycles in females undergoing ART using a fixed effect model showed that it was 14% (95% CI is 13% to 14%; I2 = 99%, p = < 0.01). The random effect model prevalence of ECF cycles was around 7% (95% CI: 4% to 10%). There was a statistically significant (25%) decrease in pregnancy rates per cycle transfer in the ECF cycle versus the non-ECF cycle group during ART [OR = 0.75, 95% CI = 0.67-0.84), p < 0.001; moderate quality evidence]. When ECF size was compared, there was a statistically significant increase in pregnancy rates if ECF size was less than 3.5 mm versus greater than or equal to 3.5 mm [OR = 13.67, 95% CI = 1.43-130.40), p = 0.02; high quality evidence]. Sub-group analysis revealed that the ECF present at the time of embryo transfer significantly decreased the pregnancy rates by 26% as compared to the group where the ECF was not present at the time of embryo transfer [OR = 0.74, 95% CI = 0.65-0.85), p < 0.001]. CONCLUSIONS: This meta-analysis proposes that the presence of ECF significantly decreases the implantation and pregnancy rates of ART cycles, and even more so if its size is greater than 3.5 mm. Interventions to decrease ECF formation or treat it have enhanced the pregnancy outcome in ART cycles. PROSPERO REGISTRATION: Date: 17th September 2020; Number: CRD42020182262.