[Declining fertility with age]. / Informer les couples. Baisse de la fertilité avec l'age.

The will to be a mother at a late age has become a real problem of society for many reasons, first and foremost because of efficient birth control, long studies and second matrimonies. In front of these still young women but quite "old" for maternity, practitioners specialized in medically assisted procreation (MAP) are often helpless, specially because most of the patients think that the MAP will be able to cure the natural decline of fertility. However, MAP's procedures cannot correct the decrease of pregnancies' rates and the increase of spontaneous miscarriages linked with the age. One of the first aims of consulting-physicians should be to give patients proper advice about fertility decline, so that women could run their life, aware of these facts.

Physiopathology of human embryonic implantation: clinical incidences.

Embryo implantation consists of a series of events promoting the invasion of the endometrium and then the uterine arterial system by the extra-embryonic trophoblast. In order for this semi-heterologous implantation to succeed, the endometrium has to first undergo a number of structural and biochemical changes (decidualization). The decidua's various constituents subsequently play a role in the embryonic implantation. The third step is the transformation of the uterine vascular system and the growth of the placenta, which will provide the foetoplacental unit with nutrients. Several physiopathological aspects will be discussed: 1) the implantation window, regulated by maternal and embryonic hormonal secretions and thus influenced by any defects in the latter: dysharmonic luteal phase, 21-hydroxylase block, abnormal integrin expression, 2) the successive trophoblast invasions of uterine vessels which, when defective, lead to early embryo loss or late-onset vascular pathologies, as preeclampsia, 3) the pregnancy's immunological equilibrium, with a spontaneously tolerated semi-allogeneic implant, 4) the impact of pro-coagulant factors (thrombophilia) on the pregnancy's progression, 5) the environment of the uterus, ranging from hydrosalpinx to uterine contractions. In summary, the least anatomical or physiological perturbation can interfere with human embryonic implantation - a very particular phenomenon and a true biological paradox.