What Causes PCOS? Scientists Might Have Found The Answer & It Has Big Implications For How We Treat It

According to recently released findings, scientists may have finally found what causes PCOS, or polycystic ovarian syndrome. The reproductive health condition affects 8 to 20 percent of adult people with ovaries, according to the National Institutes of Health, and is one of the most common causes of infertility. Right now there's no cure, and treating it is a highly specialized process. But now, scientists claim to have discovered what actually causes the condition, and a potential cure, too.

PCOS is essentially a condition where the ovaries become covered in cysts or fluid-filled bumps. It can cause a host of symptoms, from infertility to hair growth, pelvic pain, hair thinning or excessive hair growth, and hormonally induced sleep issues, because the cysts affect ovarian function and alter the body's hormonal balance. One of the big signals of PCOS is androgen excess, where someone is detected to have high levels of the male hormone androgen, but PCOS also causes insulin sensitivity and can be the stimulus for both Type 1 and Type 2 diabetes. In other words, it's a complex and difficult disorder, and it's been mysterious for quite some time. But the new study represents a major breakthrough in the reproductive condition. Here's how they figured it out.

Researchers at the French Institute found that pregnant people who also have PCOS have higher levels of a hormone called anti-Müllerian hormone in their blood — up to 30 percent more than people without PCOS. Anti-Müllerian hormone is produced by the follicles on your ovaries; we already measure it for fertility testing, as high levels of it in your blood mean that you've got more egg follicles working on your ovaries. But this was the first time that anybody had tied it to PCOS, and the French scientists wanted to test if exposure to too much anti-Müllerian hormone in utero could trigger PCOS. That would explain how it could be passed on genetically.

They decided to test the idea by using pregnant mice, raising their levels of the hormone, and testing their babies when they were born to see if they showed signs of PCOS. And results were pretty clear: the more anti-Müllerian hormone around in the system of the parent mouse, the more symptoms of PCOS the baby mice showed. Figuring out why this is the case is tricky, but the scientists believe that too much of that hormone seemed to unbalance testosterone levels in the adult mice, setting off androgen excess in their offspring. Hormones are a delicate balance, and too much of one started a chain reaction.

But the other part of this study means that we may be able to now cure PCOS, as New Scientist reports. The scientists behind this study treated the mice with PCOS using a drug called cetrorelix, which is a fertility drug often prescribed for humans. If you're having fertility treatments, you might get injections of cetrorelix to block your eggs from releasing from the ovary too early, giving them time to "grow." In the mice with PCOS, a dose of cetrorelix apparently reduced their symptoms radically and "reversed" the effects of their treatment.

Mice aren't the same as humans, but this is still a big deal. If we figure out how to lower excessive anti-Müllerian hormone levels in pregnant people, it seems, we could stop children being born with PCOS in the first place. And there might be hope for adults who are dealing with the issue right now. Instead of just being treated with cetrorelix when they want to get pregnant, people with PCOS might be given it regularly as a treatment for the condition itself. And that is really, really exciting news for people who live with PCOS.