Le fossé entre le rêve de famille et la réalité

Résumé libre de l'article publié dans Fertility & Sterility par Dominique de Ziegler (board scientifique de la Maison de la Fertilité), Sean Soktean et Paul Pirtea

La baisse de la natalité touche aujourd’hui la majorité des pays du monde. De plus en plus de femmes choisissent de ne pas avoir d’enfants, tandis que celles qui en veulent en ont souvent moins que souhaité : c’est ce qu’on appelle le “fertility gap”, ou écart de fertilité. Une partie de ce phénomène est liée à des causes sociales, mais aussi à des abandons de parcours de PMA ou à la difficulté de retenter un traitement après une première naissance. Ces interruptions réduisent les chances d’atteindre le nombre d’enfants désiré. Les professionnels de la fertilité ont donc un rôle clé à jouer : informer, accompagner et proposer des stratégies personnalisées — comme la conservation d’embryons — pour aider les couples à concrétiser pleinement leur projet familial.

Texte Original en Anglais :

Mind the gap between desired and actual family size

The population decline that affects most of the world is widely debated in the media. More than half of all countries have total fertility rates—mean number of children per woman during the reproductive years—that do not assure population replacement. These notably include all the Western European countries and North America in which the impact on total population is partially mitigated by immigration. Natality decline has already led to population shrinkage in South Corea, Japan, and China.

There are 2 major causes for the current population decline. On the one hand, there is an increasing number of women who do not want children. On the other hand, women who wish to have children often have smaller families than desired, which defines a fertility gap. The reasons for fertility gaps are multiple. Many stem from social issues that are beyond the scope of our present discussion. Certain causes of fertility gaps, however, fall within the boundaries of infertility management and are worth addressing here. These notably include women who drop out of fertility treatments and those who fail to repeat assisted reproductive technology (ART) attempts after a successful delivery.

The risk of treatment dropout is generally important, and fertility doctors should be fully cognizant of this. Couples should be warned about this risk early in their infertility management. It is worth warning patients that if it happens to others, it may also happen to them, and they should, therefore, protect themselves against this risk. Rigid therapeutic management may increase the risk of dropout. We have reviewed and criticized the consequences of blindly obeying clinical guidelines that intend to regent over, for example, the treatment of infertility associated with endometriosis (1). In this case, indeed, most guidelines recommend to first offer ovarian stimulation cycles with or without inseminations before considering ART (1). However, these guidelines ignore the fact that a large-cohort study revealed that initiating treatments with simple ovarian stimulations is associated with a high, 25%, dropout rate (2). Evidently, treatment abandonment will cause a fertility gap in the affected couples. The risk of treatment dropout should be discussed with couples upfront when reviewing the various therapeutic strategies possible. In this discussion, women’s age and ovarian reserve status, as well as patients’ intimate desires for family size, should be considered. In infertility associated with endometriosis, liberal access to ART-first options should be envisioned when it appears appropriate after discussing the pros and cons with couples. This discussion should take into account the final family size desired and discuss the possibility that treatment drop out interferes with this fulfillment.

Another risk of fertility gap stems from the possibility of failing new ART cycles after a successful delivery or not attempting to repeat ART at all. The mean age of women undergoing ART has increased in recent years, and it is not uncommon that certain returning couples fail new treatments for a second child. This is primarily due to declining ovarian function and fertility in the meantime. Esposito et al. (3) have recently reported that only one woman out of 10 having a first ART-mediated live birth repeated ART for a second child. This is far less than the attempts for new conceptions seen after a first natural live birth. These authors rightfully stress that more attention should be given to how we manage ART so as to avoid possible fertility gaps (3).

It is difficult to predict future fertility. In some years, we may be helped by AI-based programs, but these approaches are not yet ready for prime time. We should nonetheless address the possibility of a fertility gap with our patients when we initiate ART treatments. Once informed, certain couples may elect to undertake a second ovarian stimulation up front—possibly choosing a “dual-stim” protocol—to secure enough cryopreserved embryos for a second child (4). Likewise, opting for preimplantation genetic testing for aneuploidy (PGT-A) finds here an extended indication. PGT-A certainly allows to better anticipate the reproductive potential of frozen euploid blastocysts compared with untested ones (5). Hence, saving frozen euploid blastocysts allows to better predict future pregnancy chances for a second child, which patients should be aware of. Although the ultimate decision must remain in the couples’ hands, we ought to educate and help them to best achieve their wishes and not unexpectedly encounter an undesired fertility gap.

L’étude complète est disponible en anglais ici : https://www.fertstert.org/article/S0015-0282(25)00139-6/fulltext