The Grapevine

Polycystic Ovary Syndrome Cause: Hormone Exposure In Womb, Study Finds

Often linked to female infertility and menstrual irregularity, the origin of polycystic ovary syndrome (PCOS) has remained unclear. But a new study may have identified not only the cause but also a potential cure for the disorder which affects nearly one in five women around the world.

What do we know about PCOS?

PCOS is a hormonal disorder which causes the growth of cysts on the ovaries, affecting their function. Women with this condition may experience prolonged periods, excess levels of androgen (the male hormone), and pelvic pain.

"It’s by far the most common hormonal condition affecting women of reproductive age but it hasn’t received a lot of attention," said Robert Norman at the University of Adelaide in Australia.

The disorder is said to be common among obese women as well as women who have a mother or sister with PCOS. While infertility is the most well-known complication of PCOS, it can also lead to diabetes, pregnancy problems, endometrial cancer, depression, eating disorders etc.

What were the findings of the new study?

Researchers at the French National Institute of Health and Medical Research found that excess levels of a hormone called Anti-Müllerian hormone (AMH) could trigger the syndrome in the womb. They noted that pregnant women who suffer from PCOS have 30 percent higher levels of AMH than normal.

While the hormone levels are measured to test fertility, the study is the first to link it to PCOS. This also explained why it can be passed on genetically.

The study titled "Elevated prenatal anti-Müllerian hormone reprograms the fetus and induces polycystic ovary syndrome in adulthood" was published in the journal Nature Medicine on May 14.

How did the researchers test it out?

They gathered a group of pregnant mice and injected AMH into them. After they gave birth, the baby mice were examined as they grew up. It was found that the more AMH they were exposed to in the womb, the more the offsprings exhibited signs of PCOS such as infrequent ovulation and delays in becoming pregnant.

According to the researchers, the excess levels of AMH might have overstimulated a set of brain cells which led to a spike in testosterone in the female mice.

Did the study suggest a potential cure for this?

Using the same mice, the researchers tested out an IVF drug called cetrorelix which is used to regulate hormones in women. The administration of the drug could successfully reverse the effects as the mice no longer showed signs of the disorder afterward.

"It could be an attractive strategy to restore ovulation and eventually increase the pregnancy rate in these women," said Dr. Paolo Giacobini, lead investigator of the study.

The research team expressed plans for a clinical trial, preferably set to start before the end of the year, in which cetrorelix is administered to women suffering from PCOS.