Closed vs. Open Oocyte Vitrification Methods Are Equally Effective for Blastocyst Embryo Transfers: Prospective Study from a Sibling Oocyte Donation Program.

<b><i>Purpose:</i></b> To assess whether open and closed vitrification protocols are equally effective for sibling-oocyte cycles when performing blastocyst embryo transfers. <b><i>Materials and Methods:</i></b> A prospective study was set up comparing the open and the closed vitrification techniques in oocyte recipients sharing sibling oocytes between 2014 and 2016. Sibling oocytes were randomly and equally assigned into the closed group (oocytes vitrified in a closed system) or the open group (oocytes vitrified in an open system). Intracytoplasmic sperm injection was performed on all cases. Embryo transfers were performed on day 5. Power anal…