There's new information about the root of polycystic ovarian syndrome.
There's new information about the root of polycystic ovarian syndrome, and researchers believe that it is set in motion before a woman is ever even born.


Polycystic ovarian syndrome (PCOS) affects more than 200,000 women a year. I am one of those, and for years, I suffered from irregular periods and infertility, which may have been caused by the PCOS.

It can be debilitating and worldwide, it is the leading cause of infertility in women, but researchers still have found very little concrete reasoning behind why women are affected, which means that it's harder to target for elimination.

Related: What Does Polycystic Ovarian Syndrome Look Like?

But now, in a new study published in Nature Medicine, researchers from the University of Lille in France believe they may have a clue as to the origin of PCOS, and it starts before a woman is ever even born.

Researchers believe that PCOS is developed while a girl is in utero, and happens when hormones produced by the ovaries engage with some neurons in the mother's brain, causing a disruption of enzymes in her placenta. This placental disruption may then cause PCOS symptoms in the daughter she is carrying. PCOS tends to run in families, and this theory falls in line with that commonality.

The team looked at the antimullerian hormone (AMH) in rats. AMH is produced by follicles that are outside a woman's ovary. Prior research has suggested that the AMH could interact with a woman's neurons in her brain, causing her to release more luteinizing hormone (LH).

For the most part, the way to diagnose PCOS (which can often take years and has very limited treatment options) is a combination of ultrasound and blood work showing a consistently higher LH to FSH (follicle stimulating hormone) ratio. LH is the same hormone that triggers the monthly surge to prompt ovulation in a woman, but too much LH inhibits ovulation and can boost a woman's testosterone level as well.

The researchers looked four groups of women in their second trimester of pregnancy. The groups were mixed with women who did and did not have PCOS as well as who were and were not considered to be obese. They found that non-obese women who had PCOS also had AMH levels that were almost two-to-three times as high as the levels of the women in the other groups.

Related: Signs of Polycystic Ovarian Syndrome

They then looked at mice so they could then further investigate how the higher AMH levels affected the female offspring.

They found that mice who had higher levels of the AMH hormone (due to injections) also seemed to copy the hormonal imbalance they saw in the women with PCOS. They then looked at the next generation of the mice - the offspring of those with higher AMH levels - and found they suffered similar symptoms as those humans who have PCOS - elevated testosterone and disrupted ovulation.

The researchers believe that high AMH levels could stop an enzyme called aromatase in the placenta from converting testosterone to estrogen. The baby in utero is then exposed to more testosterone than would be normal and that can change her testosterone levels in the future.

Because there is such a strong correlation, the researchers believe more research should be done. That said, mice placentas don't have as much aromatase as human placentas do, so that may mean it is harder for testosterone to have that great an effect in humans, which might weaken their theory. Still, researchers agree that testosterone levels are definitely affected by AMH and that most likely plays a big role in the development of PCOS.

The team will now look at how regulating testosterone levels during pregnancy may affect the diagnosis of PCOS down the road in offspring.