Polycystic Ovarian Syndrome A Potential Cause Discovered

The polycystic ovary syndrome may be due to hormonal imbalance suffered in utero during pregnancy. This is revealed by a new study conducted by Inserm researchers.

Polycystic ovary syndrome, a hormonal disorder that affects an average of one in ten women, is characterized by very irregular menstrual cycles, ovulation disorders, high levels of testosterone sometimes leading to hyperpilosity, as well as infertility. The scientific community has been working for years to find the cause, hoping to permanently cure this syndrome rather than compensate for it with medical treatments.

And in this sense, a scientific study conducted by researchers in Lille, and published in the journal Nature Medicine, seems more than ever on the right track. A potential cause of PCOS would be overexposure to a hormone, antimüllerian hormone, during pregnancy.

Having found that PCOS often affects several women in the same family, the researchers followed pregnant women with this syndrome. They then discovered that they had an antimüller hormone (AMH) level 30% higher than normal, that is to say the average rate observed in women not affected. To determine whether this high AMH level could lead to PCOS in the offspring, the team conducted a series of experiments on mice in the laboratory.

An in utero hormonal imbalance that has repercussions in adulthood

In this way, pregnant mice were injected with antimüllerian hormone at a rate similar to that observed in pregnant women with PCOS. The young mice born of these pregnancies were followed closely, allowing researchers to find that female offspring exhibited symptoms similar to those observed in the polycystic ovarian syndrome: high testosterone levels and masculinization, irregular ovulation, infertility ... the researchers, there is little doubt: it would be this overexposure to the AMH in utero that would generate, by various mechanisms at the cerebral level, an excessive production of testosterone. Because in the embryonic development, the antimüllerian hormone has the role, in a male fetus (XY), to regress the Müller canals, which will develop into female genitalia. An excessively high rate of AMH would therefore have a "masculinizing" effect.

But the good news is that this discovery could lead to treatment: the team gave the mice a drug used in IVF to control the female hormones, cetrorelix, to remove the symptoms of PCOS. A clinical trial should begin during the year to see if these results are found in women.