The fresh or frozen eggs of the same woman are equally fertile. This is the main conclusion of a study conducted by Eugin Group researchers which won the Clinical Science Award for best clinical poster at the 35th Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE). The research went head-to-head with 800 other studies, and its principal investigator was David Cornet-Bartolomé, a member of Eugin’s Basic Research Laboratory headquartered in the Barcelona Science Park.

The reproductive results of the eggs frozen by the vitrification technique are comparable to those obtained with fresh eggs. This has been made clear in the most wide-ranging comparative study done to date using “sibling” eggs, namely eggs produced by the same woman. The research was led by Dr Amelia Rodríguez-Aranda, medical director of Eugin, and David Cornet-Bartolomé, a member of the group’s basic research laboratory operating in the Barcelona Science Park.

The researchers retrospectively analysed the reproductive results of a sample of 37,520 eggs. Half had been frozen and the other half used fresh by women undergoing In Vitro Fertilization (IVF) treatment with donor eggs (egg recipients). La meitat havien estat congelats mitjançant la tècnica de vitrificació, i l’altra meitat, utilitzats en fresc per dones en tractament de Fecundació in Vitro (FIV). The eggs belonged to 1,844 different donor women and the reproductive results were compared between “sibling” eggs, belonging to the same donor, thus making the study more reliable.

On first analysis, the research suggested that the reproductive results of the fresh eggs, in other words, the biochemical, clinical, on-going and live birth pregnancy rates, were better than those of the frozen ones.

However, when the researchers focused on those cases in which the same number of fresh and frozen eggs had been inseminated for each woman, the conclusion was that the reproductive results of the fresh and vitrified eggs were the same. In particular, the vitrified eggs recorded a live birth rate of 32.1% while that of their fresh “siblings” was 32%. 

“Given the magnitude of the sample analyzed in this study, we can emphatically state that the use of fresh eggs with respect to frozen ones offers very similar results”, said Dr Amelia Rodríguez-Aranda during the presentation of the research at ESHRE.

The study’s conclusions show that vitrification does not harm the oocyte’s fertility and thanks to their work take the opportunity to recommend that assisted reproduction clinics implement strict efficiency indicators for egg vitrification and devitrification and improve these processes in order to maximize the survival rate at devitrification.

Outstanding participation at ESHRE’s annual meeting

Last week, the city of Vienna hosted the 35th Annual Meeting of ESHRE, the European Society of Human Reproduction and Embryology. Eugin’s scientific director Dr Rita Vassena is a member of the Executive Committee of the society, which brings together thousands of specialists from all over the world. Its founders include British medical researcher Sir Robert Edwards, winner of the Nobel Prize in Medicine for the development of in vitro fertilisation therapy.

At the meeting, which attracts hundreds of industry professionals from all over the world every year, Eugin presented its latest human fertility studies. Some of the most significant studies include the research led by Marc Torra-Massana, the first to use sperm proteomic analysis techniques to analyse fertilisation failures, revealing that nine proteins (five of which are mitochondrial) are crucial for sperm fertility, and a study led by Dr Amelia Rodríguez-Aranda and Dr Désirée García, which endorses the ROPA (Reception of Oocytes from Partner) technique for women who wish to share motherhood.

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