Global fertility crisis: 54 million women over 35 unable to get pregnant

An estimated 53.6 million women aged 35 to 49 are currently unable to get pregnant, raising concerns about a global fertility crisis.

Researchers from Chongqing Medical University analyzed health data from 204 countries, for the period 1990–2023, to assess how the "burden of infertility" among women aged 35 to 49 has changed over time.

According to them, this burden has increased continuously since 1990, from about 6,001 cases per 100,000 women in 1990, to 6,907 cases per 100,000 women in 2023.

Women up to the age of 49 are often included in reproductive age statistics, as some of them still have menstrual cycles and could theoretically become pregnant. However, doctors point out that fertility drops sharply after the mid-thirties and is usually very low by the late forties.

According to data published in The Lancet Obstetrics, Gynaecology, & Women's Health, the fastest projected increase is seen in younger women within this age group.

The study divided women into three groups: 35–39 years old, 40–44 years old, and 45–49 years old. Infertility was defined as the inability to achieve a clinical pregnancy after 12 months of regular unprotected sexual intercourse.

Using the data to predict future trends, the researchers found that infertility is expected to increase in all three age groups, but the greatest increase is predicted in women aged 35 to 39.

This does not mean that women in their late thirties are more likely to be infertile than those in their forties, as fertility continues to decline with age due to a decrease in the number and quality of eggs.

Instead, the finding suggests that the overall burden of infertility is growing faster among women in the younger part of the so-called “advanced maternal age” group. This is likely related to the fact that more and more women are pushing motherhood back into their late thirties as they focus on education and careers.

But by the time they feel ready to start a family, their fertility may have already begun to decline.

In the United Kingdom, the Office for National Statistics' report on births in 2021 showed that the average age of mothers in England and Wales was 30.9 years, the highest ever recorded.

This is part of a steady increase since 1973, when the average age of mothers was just 26.4 years old.

The data also showed that births to women over 40 were more than double those to teenagers. Just five decades ago, there were nine times more teenage mothers than mothers over 40.

The authors of the new study say that obesity and stress can also affect fertility.

Greater access to fertility treatments may also have increased the number of women seeking help and the number of cases diagnosed.

The other two age groups, 40–44 and 45–49 years old, are also expected to see significant growth, bringing the total number of women affected by infertility to 79.6 million by 2036.

"The subsequent increase, from the late 1990s onwards, coincided with increased participation of women in education and the labor market, leading to widespread postponement of childbearing and, consequently, to an increase in age-related infertility," wrote the study's lead author, Yuanyuan Du.

"A temporary decline in infertility observed between 2006 and 2010 coincided with the global financial crisis, suggesting that macroeconomic instability may change the timing of when people decide to become parents."

However, this modest decline may reflect underdiagnosis due to economic barriers, rather than a real decrease in the prevalence of infertility.

"The steady increase in infertility since 2010 reflects the postponement of childbearing, combined with obesity, stress, and expanding access to assisted reproductive technologies, which have improved case detection and extended the reproductive window," the study says.

The burden of infertility is not only evident in poorer countries. Data show a shift towards higher-income and more developed countries, most likely due to later motherhood, aging populations and changing reproductive patterns.

However, women in lower-income countries continue to face significant barriers, especially because fertility testing and treatments are often more difficult to obtain.

In 2023, the most recent year analyzed, East Asia had the highest regional burden of infertility, while Australasia had the lowest.

At the country level, the Central African Republic had the highest reported burden, while Nepal had the lowest.

The researchers also emphasized that infertility in women of later reproductive age is not only a medical issue, but also has psychological, social, and economic consequences.

These include emotional stress, stigmatization, financial pressure, relationship tensions, and wider consequences for aging populations and labor market participation.

The authors argue that fertility care should be treated as a greater public health priority, with earlier detection, wider access to fertility services, and policies tailored to each country's resources and needs.