In many countries, women are having their first child later in life. This is due to changes in family planning, education, and career choices. However, this trend also brings new challenges for women who want to have children.

A woman's ability to have children decreases with age. This makes it harder to get pregnant and increases the risk of miscarriage and genetic problems. So, it's essential to find ways to assess fertility accurately.

Chromosomes carry genetic information that determines our sex. Women have two X chromosomes, while men have one X and one Y chromosome. As people age, they can lose one of these chromosomes, which can affect their health.

Losing the Y chromosome has been linked to diseases like Alzheimer's and diabetes. Losing the X chromosome has been associated with certain types of cancer and pneumonia. However, its role in fertility is not well understood.

Japanese researchers studied the link between losing the X chromosome and infertility. They found that women with infertility had a higher percentage of cells with lost X chromosomes than women who got pregnant naturally.

The researchers analyzed blood cells from 504 women aged 20-45. They compared the levels of lost X chromosomes between women who got pregnant naturally and those who didn't.

The results showed that women with infertility had higher levels of lost X chromosomes. If the level of lost X chromosomes was above 0.9%, it was harder for women to get pregnant naturally.

The researchers found that a level of 0.87% lost X chromosomes was associated with reduced chances of natural pregnancy.

They also looked at the relationship between lost X chromosomes and a hormone that indicates the number of eggs a woman has left. However, they didn't find a link between the two.

The researchers also found that lost X chromosomes were not related to another hormone that affects fertility. This suggests that lost X chromosomes may indicate a different aspect of reproductive aging.

The study's author said that combining lost X chromosome analysis with other fertility tests may help predict whether a woman can get pregnant naturally.

In the future, measuring lost X chromosomes in women with infertility may help determine whether they should try fertility treatments earlier.

Previous studies had found more X chromosome abnormalities in women with fertility problems. However, those studies used older methods that couldn't detect low levels of lost X chromosomes.

Although lost X chromosomes were only a modest predictor of fertility, they were comparable to some established fertility markers. This suggests that even low levels of lost X chromosomes may affect female fertility.

The researchers noted that more studies are needed before lost X chromosomes can be used as a clinical biomarker. Future studies should follow women over time and examine reproductive tissues directly.

More research is needed to understand the link between lost X chromosomes and fertility.

Source: Osaka Metropolitan University