Is There a Correlation between the Number of Follicular Flushings, Oocyte/Embryo Quality and Pregnancy Rate in Assisted Reproductive Technology Cycles? Results from a Prospective Study

Abstract

Objective: To determine the mean number of follicular flushings needed to retrieve the maximal number of oocytes and to investigate the correlation between the number of flushings and oocyte/embryo quality as well as reproductive outcome.

Methods: This prospective study included 154 oocyte retrieval cycles in 138 patients undergoing assisted reproductive technology treatment. During oocyte retrieval, aspirate and flushes were collected in four separate collections (A, F1, F2, F3) and inspected for the presence of an oocyte-cumulus complex (OCC). Outcome variables included oocyte recovery rate, percentage of mature oocytes, fertilization rate, day 2/day 3/day 5 embryo quality and clinical pregnancy rate/live birth rate.

Results: Out of 1,495 OCCs collected, 91% were obtained in collections A or F1. Significantly more mature oocytes were obtained in collection A (p = 0.03). The fertilization rate was similar for oocytes obtained in the four separate collections (p = 0.50). The proportion of good-quality day 2/day 3/day 5 embryos was similar (p = 0.93, p = 0.85 and p = 0.14, respectively). Clinical pregnancy rate and live birth rate were not significantly affected by the first two flushes. No live birth emanated from oocytes obtained from the third flush onwards.

Conclusion: More than 90% of all recovered OCCs were obtained after follicular aspiration followed by follicular flushing up to two times (collections A and F1). Follicular flushing may increase the oocyte recovery rate and does not have a negative influence on fertilization rate, day 2/day 3/day 5 embryo quality or pregnancy rate.