What is the medium and long-term health of children conceived through in vitro fertilization (IVF)? Forty-five years after the birth of the first test-tube baby, Louise Brown, on July 25, 1978, in the United Kingdom, and while more than 8 million people have been conceived in this way worldwide, the question is still asked. In France, 3,490 children were born in 2019 from IVF with immediate transfer, 7,292 from ICSI (injection of a sperm directly into an oocyte) with immediate transfer, and 9,701 after transfer of a frozen embryo. March 21th, the Academy of Medicine has adopted a report on this topic. Interview with Pierre Jouannet, one of its editors, also a reproductive biologist and professor emeritus at the University of Paris-Descartes.
What are the main recent developments in IVF in France?
I see three major developments over the past ten years. First, the average number of embryos transferred in utero at each attempt was reduced. At first, practitioners transferred two or even three, which greatly increased the rate of multiple pregnancies and related problems with prematurity and the health of children and mothers. Today, it is recommended to transfer only one embryo. Thanks to improved techniques, success rates have not dropped and the rate of multiple births has been halved.
The second important development is the transfer of the embryo into the uterus at the blastocyst stage. [une structure d’environ 200 cellules], which increases the chances of implantation. This implies that the embryo develops for four or five days in the laboratory, which is not necessarily without consequences.
Finally, the improvement of freezing techniques, in particular vitrification now used by all medically assisted procreation centers (PMA), makes it possible to recover better quality embryos. So much so that today the pregnancy rates obtained after transfer of frozen embryos are as good as with “fresh” embryos. This improvement can modify the embryo transfer strategy. Hormonal treatments given before egg collection are not always favorable to ensure nesting in the uterine mucosa, it was realized that success rates could be better if the embryos were all frozen immediately after IVF and then transferred later. In 2020, this so-called “freeze all” strategy was adopted in more than 20% of IVF and ICSI treatment cycles.
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