P-375 Long-term cryostorage of donor semen does not affect egg donor cycles outcomes
Authors: Freijomil B , Botia S , Fernández B , García-Faura Á , García F , Walker V , Montalvo V , Marquès B 
Published: July 2024

Abstract

Study question
Does prolonged donor semen cryopreservation impact in success rates of egg donor (ED) IVF cycles?

Summary answer
Prolonged donor semen cryopreservation does not affect good quality embryos or pregnancy rates in ED-IVF cycles.

What is known already
Births from cryopreserved semen stored for over 20 years have been documented. In 2004, a case of an IVF birth with semen frozen for 21 years was reported, and in 2005 another case with an IUI birth using semen frozen for 28 years was published. Recently, in 2019, a child born through IVF with semen frozen for over 26 years was reported in UK. In 2019, a study found that prolonged storage of these samples did not affect the outcomes of IVF with own eggs or IUI.

Study design, size, duration
We analysed data from 969 ED-IVF cycles performed at our centre between 2007 and 2022. Initially, cycles were classified into two independent groups of study to eliminate the impact of differences in embryo culture time. Group 1 or short culture (until Day 3) included 511 cycles from 2007 to 2013, and Group 2 or long culture (until Day5/6) included 458 cycles from 2014 to 2022.

Participants/materials, setting, methods
Donor oocytes were inseminated by ICSI using donor sperm from our bank. We analysed the relationship between the years of semen cryopreservation and the number of good quality embryos in both groups using Pearson correlation coefficient. Afterwards, the groups were divided into three subgroups based on the years of cryopreservation: 0-&lt;3, ≥3-5, ≥5. Pregnancy and term pregnancy rates were calculated, and their relationship with time of semen cryopreservation were analysed using the Chi-square statistic.

Main results and the role of chance
No relationship was found between the years of cryopreservation and the number of good quality embryos in either group (Group 1 r=-0.05 and Group 2 r = 0.04). Pregnancy rates for the three subgroups 0-&lt;3, ≥3-5, ≥5 were as follows: 219/454(48.24%),17/ 39(43.59%) and 6/18(33.3%) respectively in Group 1 and 141/213 (66.2%), 62/104 (59.62%), and 85/141 (60.28%) in Group 2. No statistically significant relationship was found in either group (Group 1 p-value=0.41 and Group 2 p-value=0.38). Term pregnancy rates for the three subgroups 0-&lt;3, ≥3-5, ≥5 were as follows: 139/219 (63.47%), 10/17 (58.82%) and 4/6 (66.67%) respectively in Group 1 and 89/141 (63.12%), 39/62 (63.12%) and 56/85 (65.88%) in Group 2. No statistically significant relationship was found in either group (Group 1 p-value=0.91 and Group 2 p-value=0.90). The findings of this study indicate that prolonged donor semen cryopreservation does not appear to have a negative impact on success rates in ED-IVF cycles, both in terms of embryo development, and pregnancy and term pregnancy rates.

Limitations, reasons for caution
In Group 1 there was a big difference in sample size between subgroups, but it was due to the nature of the study.

Wider implications of the findings
Despite it seems that prolonged cryopreservation of semen does not affect embryonic viability, there is a lack of many molecular studies to ensure that this does not impact in cellular mechanisms or epigenetics.

Trial registration number
Not Applicable