The most common cause of female infertility, polycystic ovary syndromeIt could be caused by a hormonal imbalance before birth. The discovery has led to a cure in mice, and a trial in women will begin later this year.
Polycystic ovary syndrome affects one in five women worldwide, three-quarters of whom have problems getting pregnantThe condition is generally characterized by high testosterone levels, ovarian cysts, irregular menstrual cycles, and difficulty regulating blood sugar, but its causes have long been a mystery. "It is by far the most common hormonal condition affecting women of reproductive age, but it hasn't received much attention," says Robert Norman of the University of Adelaide in Australia.
Now, a new study conducted by Paolo Giacobini and other researchers at the French National Institute of Health and Medical Research reveals that The syndrome can be triggered before birth by excessive exposure in the womb to anti-Müllerian hormone.
Researchers discovered that pregnant women with polycystic ovary syndrome (PCOS) have anti-Müllerian hormone (AMH) levels 30% higher than normal. Since PCOS is known to be hereditary, they wondered if this hormonal imbalance during pregnancy could induce the same condition in their daughters.
To test this idea, they injected excess anti-Müllerian hormone into pregnant mice. As their female offspring grew, they exhibited many of the characteristics of polycystic ovary syndrome, including delayed puberty, infrequent ovulation, delayed miscarriage, and decreased fertility.
The excess hormone appeared to trigger this effect by overstimulating a set of brain cells that raise testosterone levels.
The research team was able to reverse this effect in mice using cetrorelix, an IVF drug routinely used to control female hormones. After treatment with this drug, the mice no longer showed symptoms of polycystic ovary syndrome.
The team is now planning a clinical trial of cetrorelix in women with this condition, which they hope to begin before the end of the year. “This could be an attractive strategy for restoring ovulation and ultimately increasing pregnancy rates in these women,” says Giacobini. “It’s a radical new way of thinking about polycystic ovary syndrome and opens up a whole range of opportunities for further research,” says Norman.
The fact that polycystic ovary syndrome is passed from mothers to daughters through hormones in the womb would explain why it has been so difficult to identify any genetic cause of the disorder"It's something we've been stuck on for a long time," Norman says.
The findings may also explain why women with the syndrome seem to conceive more easily in their late 30s and early 40s, Norman says. Anti-Müllerian hormone levels are known to decline with age, typically signaling reduced fertility. But in women who start with high levels, age-related declines can bring them into the normal fertility range, though this still needs to be evaluated, according to Norman.
This post is a translation of Original article published in New Scientist.