New research shows that exposure to excess amounts of a particular hormone to female babies in utero may play an important role in the onset of polycystic ovary syndrome (PCOS) in those individuals in adulthood.
However, the research also shows promise of being able to block the hormone, potentially reversing some of its negative effects.
Published in Nature Medicine, the research showed that exposure to excess levels of anti-Mullerian hormone (AMH) during pregnancy leads to a cascade of changes that alter the brain, the ovaries and the placenta, leading to PCOS in females.
PCOS is a common condition, affecting around one in 10 women of reproductive age worldwide. PCOS has reproductive, metabolic and psychological features and is often characterised by excess body and facial hair growth, weight gain, and infertility.
The research, led by the University of Lille, France, showed that AMH levels during pregnancy are two to threefold higher in women with PCOS, compared to women without the condition.
A woman with PCOS has a higher risk of having a daughter with PCOS. However, it has been unclear as to how the condition is passed on.
To test whether in utero exposure to higher levels of AMH might lead to PCOS later in life, the researchers exposed pregnant mice to AMH and studied the features of female offspring at adulthood. They noticed that females displayed many of the features of PCOS, including later puberty, infrequent ovulation, delays in falling pregnant, and fewer offspring.
The researchers then tested whether they could reverse PCOS symptoms by treatment with cetrorelix, a hormone blocker used to modify women's hormones. They discovered that major PCOS symptoms such as oligo-anovulation (inconsistent or irregular ovulation) and hyperandrogenism (excess levels of male sex hormones, ie, testosterone) could be reversed.
University of Adelaide Professor for Reproductive and Periconceptual Medicine, Robert Norman, said the successful research using mice had now paved the way for a clinical trial in humans.
"Being able to show a reversal of PCOS symptoms in female mice offspring, through the use of hormone blockers, is an encouraging model and a clinical trial in women with PCOS will now take place in Europe," Prof Norman said.
"The logic behind the clinical trial is to block the signals from the brain that may lead to increased testosterone."
Prof Norman said the research would provide "many opportunities" for further investigations regarding PCOS treatment, especially in relation to fertility.
"Although this research is many years away from providing a therapeutic outcome, the potential is significant from a fertility treatment perspective, as well as potentially halting the passing on of PCOS from one generation to another," Prof Norman said.
Regarding women who have PCOS now, Prof Norman said lifestyle factors such as being physically active, maintaining a healthy weight, and enjoying a balanced eating plan all have proven benefits in reducing the symptoms of PCOS.
"While this research adds an exciting dimension to PCOS management in the future, we want to reassure women suffering from PCOS today that there are effective ways to manage their condition successfully," he said.
To learn more about PCOS, visit our PCOS webpages.