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Updated: Jun 28, 2026
Morphometric Protocol for the Objective Assessment of Blastocyst Behavior During Vitrification and Warming Steps
Published on: February 28, 2019
Embryo warming using an ultrafast protocol: perinatal outcomes from 1020 births from a single UK IVF centre
Elena Linara-Demakakou1, Trina Shah1, Balsam Al-Hashimi1
1London Women's Clinic, London, UK.
Research Question:
Does the use of embryo warming with an ultrafast protocol influence clinical and perinatal health outcomes when compared with conventional warming protocols?
Design:
A retrospective cohort study was conducted at a single IVF centre evaluating frozen embryo transfer cycles performed between November 2023 and December 2024. Traditionally vitrified embryos were subsequently warmed using either traditional or ultrafast protocols. Live birth rate and perinatal outcomes including gestational age, neonatal birthweight and twin rates were calculated.
Results:
A total of 4061 blastocyst warming events in 3657 embryo transfer cycles were analysed, of which 2761 involved warming using an ultrafast protocol and 1300 warming using a traditional protocol. Embryo survival was 99% following both methods. Live birth rates were comparable (37% versus 35.4%). No significant differences were observed in perinatal health outcomes.
Conclusions:
Warming with an ultrafast protocol provides excellent embryological and clinical outcomes equivalent to those achieved with traditional warming, without evident adverse effects on perinatal health outcomes. These findings support the efficiency of the ultrafast protocol as a routine approach in assisted reproduction and its potential to maintain optimal patient outcomes.
