Daughters of Women With PCOS Five Times More Likely to Develop Condition, Scientists Say

Scientists believe women whose mothers have polycystic ovary syndrome (PCOS), one of the leading causes of infertility, are five times more likely to develop the condition.

Researchers studied women in Sweden and Chile, as well as mice, to arrive at their conclusion on the condition which on average affects 17 percent of women of reproductive age. The condition is characterized by enlarged ovaries— which may have fluid-filled sacs surrounding the eggs—irregular periods and high levels of the hormone androgen. As well as issues with menstruating—which can cause problems getting pregnant—those with PCOS are also more likely to develop type 2 diabetes and high cholesterol, have excess hair on the body and face, thin hair on the head, develop acne and gain weight.

From birth to adulthood, the team followed 21 women in Chile who had mothers with PCOS, and compared them with 14 who didn't. They also studied 29,736 women from a Swedish patient database, 2,275 of who had mothers with PCOS.

In both the Swedish and Chilean cohorts, the daughters of women with the condition were five times more likely to have PCOS than those who didn't.

To find out more about the potential mechanism behind this link, the team also studied mice with PCOS-like traits. They found mice exposed to androgen hormones in the womb were more likely to give birth to babies with the condition. This was passed on for up to three generations.

The researchers also used DNA samples from the participants of the Chilean study, and found four of the genes expressed across all generations in mice cells followed the same expression pattern in humans.

Obesity wasn't found to be linked to PCOS in the study. It's unclear what causes PCOS, but the two conditions are thought to be linked.

Co-author Elisabet Stener-Victorin, professor in the Department of Physiology and Pharmacology at Sweden's Karolinska Institutet, explained to Newsweek the team has studied the potential causes of PCOS for many years.

In a separate study, they showed that women with the condition have higher levels of androgens, irregular menstrual cycles, and abnormally shaped ovaries. PCOS patients also had a higher chance of being insulin resistant, and having enlarged fat cells independent of obesity, as well as differences in their fat and muscles related to gene expression.

Stener-Victorin said the team's past work in rodents suggested encountering excess androgen in the womb may change gene expression, and increase the risk of first-generation offspring developing PCOS.

That inspired their latest investigation aimed at seeing if PCOS-like symptoms could be passed down to the third generation of mice.

"This study indicates that it is rather intrauterine/germ cell factors than genetic factors that contribute to the development and transmission of the disease," Stener-Victorin explained.

Commenting on the potential uses of the research, Stener-Victorin said the genes identified could serve as potential biomarkers to predict the development of PCOS and have the potential to be used for screening, "although it requires further validation."

Stener-Victorin said a genetic test for PCOS wouldn't be possible off the back of the current research as several candidate genes were identified.

"It might be in the future, but more research is needed here," said Stener-Victorin, who co-authored the paper with Qiaolin Deng, associate professor in the department of Physiology and Pharmacology at the Karolinska Institutet.

The work could also help the development of a treatment to prevent PCOS being passed on, she added.

Stener-Victorin highlighted the fact that PCOS affects up to 17 percent of women, but it is under-diagnosed. On average, women must visit three doctors before they are told they have PCOS, she said.

"It is of importance to increase the awareness of PCOS and its co-morbidities in the general community. It is not OK that it takes two years and several doctors before you are even diagnosed," said Stener-Victorin.

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A stock image shows a mother and daughter sitting on a bed. Research suggests PCOS might be passed down from mother to daughter. Getty