Polycystic ovary syndrome (PCOS) may be the result of exposure to higher levels of a hormone before birth, according to researchers at the French National Institute of Health and Medical Research. Those same researchers – who published their findings in the journal Nature Medicine – believe that a common IVF drug known as cetrorelix could treat PCOS in women and help them overcome fertility issues.
Up to one in every five women around the world suffers from PCOS, which often results in ovarian cysts, irregular menstrual cycles and fertility problems. Fertility treatments can be used to help women with PCOS get pregnant, however success rates are low at about 30 percent over the course of five menstrual cycles. While the condition is associated with high levels of testosterone, its underlying cause was unknown – until now.
“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.
In the course of their research, the French scientists found that levels of anti-Müllerian hormone in women with PCOS are about 30 percent higher than healthy individuals. Because women with PCOS often have female relatives with the condition, the researchers postulated that overexposure to anti-Müllerian hormone while in the womb could be a potential cause for the condition.
Using pregnant mice as model organisms for this proposed phenomenon, the research team injected them with anti-Müllerian hormone to test its effects on the reproductive health of their offspring. Once the resulting female offspring reached sexual maturity, they showed many of the same signs as women with PCOS, including delayed puberty, irregular ovulation and conception issues.
The researchers believe that excess anti-Müllerian hormone may promote the release of higher levels of testosterone, which lead to the symptoms of PCOS. By identifying this potential causative mechanism behind PCOS, the researchers were able to propose and test a treatment option for the condition.
To test this treatment, the researchers dosed the PCOS mice with cetrorelix, an IVF drug used to regulate hormones. They found that symptoms of PCOS in the mice ceased after treatment with cetrorelix.
“It’s a radical new way of thinking about polycystic ovary syndrome and opens up a whole range of opportunities for further investigation,” said Norman. “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.”
Armed with their promising preclinical results, the researchers plan to test cetrorelix for this indication in women with PCOS in an upcoming clinical trial.
“It could be an attractive strategy to restore ovulation and eventually increase the pregnancy rate in these women,” said lead researcher Paolo Giacobini of the Laboratory of Development and Plasticity of the Neuroendocrine Brain at the University of Lille in France.
According to Norman, the research findings may also offer some insight into why women with PCOS see an increase in fertility when they’re in their late 30s and early 40s, which is a time when other women may be seeing a decline in their ability to conceive. Since anti-Müllerian hormone levels drop as a woman ages, it’s possible that this decrease brings them into the optimal range which women without PCOS may have already experienced during their 20s and 30s.