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Résumé: Objectif: Les transferts d’embryons congelés permettent d’optimiser les taux de grossesse par ponction. En France, 60 % des cycles de transfert s’effectuent en cycle stimulé. Le but de ce travail est d’évaluer les issues des transferts d’embryons congelés en cycle spontané, substitué et stimulé. Patientes et méthodes: Cette étude rétrospective inclut des patientes âgées de 18 à 43ans ayant eu un transfert d‘embryon congelé entre le 1er janvier 2008 et le 31 décembre 2008. Trois protocoles de transfert ont été utilisés : le cycle spontané (groupe 1), le cycle substitué (groupe 2) et le cycle stimulé (groupe 3). Les caractéristiques des couples, les paramètres embryonnaires et les données des cycles de transferts, ainsi que leurs issues, ont été évalués. Résultats: Parmi les 333 patientes, on comptait 132 dans le premier groupe, 24 dans le deuxième groupe et 177 dans le troisième groupe. Après contrôle de l’homogénéité des trois groupes, on retrouvait des taux de grossesses (respectivement 20,49 vs 13,04 et 11,32 % ; p =0,0348) et d’accouchements (respectivement 13,93 vs 8,7 et 6,29 % ; p =0,0314), significativement plus élevés en cycle spontané. Discussion et conclusion: Actuellement il n’y a pas de réel consensus sur la meilleure technique de préparation endométriale en vue de transferts d’embryons congelés. Nos résultats plaident en faveur des transferts en cycle spontané chez les patientes normo-ovulantes. Les cycles spontanés permettent d’obtenir de bons taux de grossesses tout en minimisant les coûts et les effets secondaires. [ABSTRACT FROM AUTHOR]

Abstract: Oocyte donation is offered to patients with premature ovarian failure to achieve pregnancy when no other assisted reproductive technology is possible. Some clinical and biological factors have been identified for influencing the outcome of oocyte donation cycles. Embryo implantation depends on embryo quality, method for the embryo transfer, and endometrial differentiation. In our center, the oocyte recipients receive for the endometrial preparatory cycle the same treatment that for the patients undergoing frozen embryos transfers, with good clinical pregnancy rates, about 35% per transfer. Estrogen and progesterone supplementation with GnRH agonist down regulation are used in synchronized protocols or for frozen embryos transfers. The synchronization between recipient''s endometrium and donor''s ovarian stimulation is very restrictive. Nowadays, the oocytes vitrification lithens the oocyte donation process: the endometrial preparation has a limited duration and is well controlled, and embryos that are transferred are all fresh embryos. [Copyright &y& Elsevier]

In 2005–2006, 905 punctures of oocytes were realised in the Assisted Reproductive Technology Centre of Rennes Hospital in France, the source of 173 pregnancies after fresh embryos transfers and 185 pregnancies after frozen embryos transfers. The single-embryo transfer (SET) was proposed in all patients aged less than 38 years with at least two embryos type I or II on the first two cycles. Sixty-three percent of patients (n =293 cycles) chose the SET with 21.5% pregnancies through fresh embryo transfer. The SET with frozen embryos has been completed on 708 cycles with 16.8% of pregnancies per transfer. The cumulative rate of pregnancies by puncture is 39% and the overall risk of multiple pregnancies has dropped to 12%. The SET associated with an effective embryo cryopreservation therefore allows to reduce the risk of multiple births while maintaining a satisfactory pregnancy cumulative rate. [Copyright &y& Elsevier]

The aim of infertility treatment is clearly to obtain one healthy baby. If the transfer of a top quality single embryo could provide a baby to all the patients, there would be no more discussion. The problem is that, nowadays, French pregnancy rates after fresh embryo or frozen embryo transfer are not the same as in Nordic countries. All studies show that in unselected patients, single embryo transfer decreases twin pregnancy rate but decreases pregnancy rate too. Pregnancy rate is dependent on embryo quality, women’s age, rank of IVF attempt (clear data) but also on body mass index, ovarian reserve, smoking habits. All these data cannot be taken into account in a law. That is the reason why a flexible policy of transfer adapted to each couple is preferable. Each couple and each IVF team are unique and must keep the freedom to choose how many embryos must be transferred to obtain healthy babies, and to avoid twin pregnancies but without demonizing them. [Copyright &y& Elsevier]

Abstract: Over the last decade, several methods have been designed to improve the survival rate of vitrificated embryos. Although some teams have succeeded, the main remaining drawback of these methods is that they do not provide a leak proof environment for cryopreserved biological samples. To respond to that demand in respect with the European reglementation, the Cryo Bio System company (CBS) designed the HSV High Security Vitrification Kit™ (HSV). This system is composed of three distinct parts, a High Security thermal-autogenic sealed clear straw, a capillary with its extremity in form of a gutter, and an introducer that can be mounted on the manipulation rod before introduction into the straw. In this study, we confirmed that the CBS vitrification kit is a suitable method for vitrification in association with a small amount of cryoprotector enriched viscous media such as 25 μM Ficool 400, 750 mM Sucrose, 1% Bovine albumin, 20% Dimethyl Sulfoxide and 20% Ethylene glycol in a Phosphate buffered saline solution. We also evaluated the speed of the temperature decrease during vitrification in comparison with four other commercially available non-aseptic methods and showed the protective role of the CBS system during transfer. These physical data have now been confirmed biologically by P. Vanderzwalmen who obtained easily reproductible good results with human embryo using our method. Today, the HSV represents the unique aseptic alternative device (EC and FDA approved) for embryos, oocytes, and biological samples vitrification. [Copyright &y& Elsevier]