P-210 Development of a new device for automatic vitrification of oocytes
Authors: Dosdá Munuera C , Mendoza Lupiáñez L , Cabello Vives Y , Guerrero Sánchez J , Sales Fidalgo J , García Alonso D , Cancio Villalonga D , Fernández Blanco G , Carasa P , Álvarez Diaz S , Matthys L , Horcajadas J.A , Munné S 
Published: June 2022

Abstract

Study question
Could an automatic vitrification device prevent human errors and lead to better results and the same survival rates to avoid variability between reproductive centres?

Summary answer
Developing an automatic vitrification device using Kitazato vitrification/warming medium could optimize survival rates and outcome, regardless of the centre or user using the technique.

What is known already
Vitrification is the most common technique used daily in assisted reproduction clinics for oocytes and embryos cryopreservation. This procedure is becoming more popular since women are delaying motherhood and they want to preserve their fertility. The most used methodology worldwide is the Kitazato protocol, which has reported the best survival rates (&gt;90%).
Although these results are attractive, the procedure involves several manual steps, which requires highly skilled and trained embryologists to be as reproducible as possible. It exists variability between users according to their experience and between clinics so, a device that ensures reproducibility, safety and efficacy is the future.

Study design, size, duration
The automated device and the microfluidic chip were designed by our team. During 3 weeks, 210 mice zygotes were used in the study to mimic oocyte behaviour because of their greater availability, similar features and their use for trials of biocompatibility of materials for subsequent use in human samples. They were divided in 2 groups to compare manual and automated vitrification using Kitazato media. Both groups were warmed manually according to standard Kitazato protocol.

Participants/materials, setting, methods
Mice zygotes (210) were divided in 2 groups: A) Manual control (n = 103) with standard vitrification protocol by Kitazato; B) Automated group (n = 107), following a microfluidic protocol performed with Kitazato media. All the zygotes were stored with the same vitrification device: Cryotop by Kitazato. After their storage in liquid nitrogen, both groups were warmed manually following the standard Kitazato thawing protocol. Chi square test was performed to compare survival and blastocyst rates between groups.

Main results and the role of chance
The manual control, Group A (n = 103), showed 99% survival rate and 92.2% blastocyst rate vs. 99% and 85.8% respectively, when performing the automatic protocol, Group B (n = 107). Chi square test was performed in order to compare survival and blastocyst rates between protocols. No significant differences were found between groups A and B comparing survival rate (p = 0.9985) or blastocyst rate (p = 0.7257).
Our device for the automation of oocyte vitrification offers promising results on survival and blastocyst rates, being similar to manual protocols routinely used in IVF laboratories.

Limitations, reasons for caution
This is the previous step before moving on to human studies to see if the same results can be reproduced. Subsequently, it will be necessary the approval of a clinical trial to verify that pregnancy and live birth rates are similar to those obtained with the non-automated manual protocol.

Wider implications of the findings
The use of an automated device that allows the adequate exposure to the different vitrification solutions, obtaining at least the same outcome rates, would let the development of a standardised and reproducible protocol that would reduce human error and variability between reproductive clinics and embryologists.

Trial registration number
Not applicable