Equivalent clinical outcome after vitrified-thawed blastocyst transfer using semi-automated embryo vitrification system compared with manual vitrification method.

Atsuko Miwa,Yuta Kasahara,Hiroshi Hayashi,Miwa Hidaka,Yukiko Noguchi,Yuusuke Mori,Takuma Sato,Kayo Hosoya

doi:10.1002/rmb2.12320

Atsuko Miwa, Yuta Kasahara + Show 6 more

Open Access

https://doi.org/10.1002/rmb2.12320

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Abstract

PurposeThis study compared Gavi®, an automated system for the equilibration and dehydration steps of vitrification, and a manual vitrification procedure in terms of effects on clinical outcomes.MethodsThe authors retrospectively compared survival rate, and clinical and perinatal outcomes after vitrified‐thawed single blastocyst transfer between Gavi® (G method) in 398 cases and Cryotop® (C method) in 208 cases.ResultsWith C and G methods, survival rates were 98.6% (208/211) and 99.3% (398/401), total pregnancy rates were 34.3% (72/208) and 33.4% (133/398), and total miscarriage rates were 22.2% (16/72) and 24.8% (33/133), respectively. Among women <35 years old, pregnancy rates were 41.1% (30/73) and 40.5% (62/153) and miscarriage rates were 13.3% (4/30) and 16.1% (10/62) with C and G methods, respectively. Among women ≥35 years old, pregnancy rates were 31.1% (42/135) and 29.0% (71/245) and miscarriage rates were 28.6% (12/42) and 32.4% (23/71) with C and G methods, respectively. C and G methods showed no significant differences in any trials, including gestational age, cesarean section rate, or birthweight (P > .05 each).ConclusionsGavi® showed comparable clinical outcomes to the manual vitrification method and can be considered an alternative vitrification procedure in assisted reproductive technology.

Highlights

The history of embryo freezing started with a report in 1972 by Whittingham et al,[1] showing that mouse blastocysts survived a freeze-thaw cycle
No significant differences in pregnancy or miscarriage rates were evident between C and G methods for any age-groups
There was no significant difference between C and G methods in each age-group

Summary

| INTRODUCTION

The history of embryo freezing started with a report in 1972 by Whittingham et al,[1] showing that mouse blastocysts survived a freeze-thaw cycle. In 2000, Yoon et al reported a healthy pregnancy and live birth of a human embryo using vitrification.[7,8] By preventing ice crystal formation, blastocysts have shown an extended survival rate after thawing compared to programmable rate freezing used in ART.[9] clinics familiar with vitrification reportedly show around a 90% blastocyst recovery rate and pregnancy and live birth rates equal to or higher than those with fresh embryo transfer.[10,11,12]. By automating embryo vitrification with Gavi®, it is considered to eliminate variations in results due to the skill of the embryologists and human error, and to shorten the working hours of the embryologists, so that even a facility with small number of embryologists can expect improving work flow in vitrification procedure and consistent clinical outcome. Learning time Human error possibility Contamination risk Vitrification speed Vitrification cost

| Study design

| Background characteristics of patients

Findings

| DISCUSSION