La fécondation in vitro : aujourd'hui et demain

Abstract

Les techniques de fécondation in vitro ont connu en quelques années d’importants développements. Une solution thérapeutique peut être proposée dans presque toutes les stérilités, y compris dans les stérilités masculines les plus sévères du fait de la mise au point de l’injection intracytoplasmique de spermatozoïde (ICSI). Les traitements actuels de stimulation sont lourds et entraînent des complications (grossesses multiples et syndrome d’hyperstimulation ovarienne) ainsi que des effets secondaires. Le devenir des grossesses et des enfants est altéré par une grande fréquence de grossesses multiples mais le pourcentage de malformations et les indices de développement sont comparables à ceux des enfants issus de grossesses spontanées de rang équivalent. Les progrès attendus dans les années à venir concernent le développement de la congélation d’ovocyte ou de tissu ovarien, la maturation ovocytaire (ou folliculaire) in vitro et la simplification des protocoles actuels de stimulation.

In the past 20 years, important progress has been accomplished in the in vitro fertilization (IVF) technique. A treatment can be proposed in almost all the aetiologies of infertility. Beside the classical in vitro fertilization, the breakthrough of intra-cytoplasmic spermatozoa injection (ICSI) has revolutionized the management of male infertility. Today, pregnancies can be achieved with a single spermatozoa which can be obtained in the epididimys or even in the testicular tissue. Ovarian stimulation is mandatory for IVF and leads to complications and side-effects. The transfer of more than one embryo increases the chance of pregnancy, but is followed by an higher incidence of multiple pregnancies with adverse obstetrical and pediatrical outcome. Most of the follow up studies of children conceived with ICSI have found malformation rates and developmental index comparable to those observed in the overall population. One of the problem is the increased incidence of chromosomal abnormalities in male infertility. A small increase in the sex chromosome abnormalities has been reported. More recently, microdeletions of the Y chromosome have been linked to male infertility and the potential transmission of the defects to the male decendance should be taken into account. Eggs donation is proposed to women with absent or inactive ovaries. The oocytes of young and fertile donors allow the occurrence of pregnancies in these patients. In France, the Bioethic Law of 1994 have put the practice of egg donation under heavy reglementations. Egg donation should be free of charge and fees, anonymous and the obtained embryos must be frozen for a period of 6 months to allow the control of the HIV and Hepatitis tests. This mandatory freezing/thawing procedure ensures a complete viral safety but clearly reduces the success rate of the procedure. Assisted reproductive technologies are now regulated by the French Bioethic Law. All the centers should be authorized as well as the clinicians and embryologists who receive a specific autorization to each available techniques. In the near future, progresses will concern the oocytes and ovarian tissue frezzing, in vitro maturation of oocytes and embryos. There is also a clear demand for simplification of the current stimulation regimens to diminish the side-effects, the complications and the heavy psychological impact of the assisted reproduction techniques. [References: 32]