Scientists Think They Have Discovered The Cause Of PCOS

Polycystic ovary syndrome (PCOS) is the most common hormonal disorder affecting women of reproductive age. Between 5 and 10 percent of women experience the condition. Until recently, however, its root causes have been poorly understood.

According to the Mayo Clinic, PCOS can cause “infrequent or prolonged menstrual periods, as well as excess male hormone (androgen) levels,” which can result in symptoms such as excess facial and body hair and occasionally severe acne. Other common symptoms include weight gain, irregular periods, fatigue and hair loss.


PCOS can be difficult to diagnose, as there is not one definitive test, but rather, doctors diagnose based on symptoms.


A recent study published in the journal Nature Medicine found that the condition may be tied to elevated prenatal anti-Mullerian hormone — a hormone secreted by cells in developing egg sacs — while a baby is in utero. Experts think it may reprogram the fetus and induce PCOS in adulthood.

The finding could be a big step forward in doctors’ understanding and possible treatment of the condition.

in vitro fertilization photo
Getty Images | Sandy Huffaker

Infertility Issues

PCOS is a leading cause of infertility. If a woman with PCOS does become pregnant, she is at a higher risk for a miscarriage and premature delivery.

Other complications during pregnancy include gestational diabetes or high blood pressure as well as non-pregnancy-related complications, including Type 2 diabetes, depression and abnormal uterine bleeding.


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Hormone Study

Paolo Giacobini at the French National Institute of Health and Medical Research and his colleagues conducted experiments on mice to reach their conclusions. They found that pregnant women with PCOS have 30 percent higher levels of anti-Mullerian hormone than normal. Since PCOS tends to run in families, they wanted to see if the imbalance during pregnancy would result in the condition being passed on to daughters.

They injected excess anti-Mullerian hormone into pregnant mice, and when those offspring matured, they began to display many of the common signs of PCOS, including infrequent ovulation and reduced fertility. The mice were then treated with a drug commonly used in in-vitro fertilization (IVF), cetrorelix, which stopped the PCOS symptoms.


“These findings highlight a critical role for excess prenatal [anti-Mullerian hormone] exposure and subsequent aberrant GnRH receptor signaling in the neuroendocrine dysfunctions of PCOS, while offering a new potential therapeutic avenue to treat the condition during adulthood,” the researchers wrote.

In order for the full implications of the study to be realized, more research is needed. Still, this information could be helpful for researchers going forward.

pregnancy photo
Flickr | saralunaa

“It’s a radical new way of thinking about [PCOS] and opens up a whole range of opportunities for further investigation,” Robert Norman, a researcher at the University of Adelaide in Australia who was not involved in the study, told New Scientist. “If the syndrome is indeed passed from mothers to daughters via hormones in the womb, that could explain why it’s been so hard to pinpoint any genetic cause of the disorder. It’s something we’ve been stuck on for a long time.”

Here’s hoping that this new research leads to better treatments for the many women suffering from this condition.