Larger oocyte cohorts maximize fresh IVF cycle birth rates and availability of surplus high-quality blastocysts for cryopreservation.

Research Question: How does oocyte cohort size affect IVF treatment outcomes?

Design: Retrospective cohort analysis of 10,193 fresh autologous oocyte retrievals among good-prognosis patients <35 years from 2009 to 2015. The primary outcome was live birth from a fresh transfer; secondary outcomes included cumulative live birth potential from the retrieved cohort and frequency of severe ovarian hyperstimulation syndrome (OHSS).

Results: Live birth per fresh transfer increased as the oocyte cohort increased up to 11-15 oocytes, then plateaued.

Blastocyst development after vitrification of multipronuclear zygotes using the Flexipet denuding pipette.

The purpose of this study was to demonstrate the safety and efficacy of vitrification of human pronuclear stage (PN) embryos in the human assisted reproduction laboratory. Using single pronucleate (1PN) and three pronucleate (3PN) zygotes, the impact of vitrification in the Flexipet denuding pipette (FDP) as a carrier was assessed in terms of survival, embryonic development and blastocyst formation when compared according to the PN number, and unvitrified controls. A total of 65 1PN and 152 3PN zygotes were vitrified; after warming 82% (53/65) of 1PN and 90% (137/152) of 3PN survived.