Controlled ovarian stimulation

The first child born with IVF was a girl, Louise Brown, the result of the fertilization in a test tube of a single egg taken during a natural menstrual cycle. Further research showed that the chances of pregnancy increased dramatically when several fertilized oocytes were transferred into the uterus, rather than just one. Since then, the normal practice of IVF has consisted in targeted stimulation of the ovaries with hormones, so that a certain number of mature oocytes can be collected.

This is known as controlled ovarian stimulation (COS). Unlike simple unstimulated (“natural”) cycles or those stimulated with clomiphene, COS maximizes the number of healthy oocytes that can be harvested and thus increases the chances of success. COS is, today, the first step in most IVF procedures.

In Del Paese, however, the introduction, with law 40/2004, of the obligation to implant all the embryos produced (up to a maximum of three) made the procedure more complex by prohibiting the freezing of supernumerary embryos. The sentence 151 of 2009 of the Constitutional Court declared this limitation partially inapplicable but in the absence of a regulation that officially acknowledges what was stated by the judges, each center behaves according to its own ethical criteria. It should be remembered that today, however, most of the centers have resumed freezing embryos. Before resorting to any treatment it is good to ask your doctor what are the procedures provided by the chosen center.

Egg freezing (a useful practice to avoid "wasting" the eggs produced in each cycle without necessarily fertilizing them all) has made great strides in recent years, but studies continue to show success rates lower than those obtained with frozen embryos. The freezing of oocytes or ovarian tissue, however, is a procedure that should be proposed as a preventive measure to all young women who have to undergo treatments potentially harmful to fertility, such as anticancer chemotherapy.

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