Eighty million women may be affected by infertility by 2036

The number of cases of female infertility in women aged 35-49 is predicted to increase drastically over the next decade, according to new research.

An international project led by researchers in China has mapped the global rise of infertility in women aged 35-49 years. They aimed to identify the specific patterns associated with this increase, and predicted that by 2036, 79.6 million women could be affected.

'As population ageing and socioeconomic transitions accelerate, the number of women exposed to advanced-age infertility risk is rising, expanding its public health relevance,' said the authors of the paper, published in The Lancet.

Using data from the Global Burden of Disease study, they analysed data from 204 countries and regions between 1990 and 2023 to track the impact of both public health and socioeconomic factors on this phenomenon.

Decreased fertility with age is largely attributed to the sharp decline in ovarian reserve that occurs with advancing maternal age, as well as decreasing egg quality. Both factors contribute to reduced natural fertility, increased risk of miscarriage and decreasing success of fertility treatments such as IVF.

Among all 204 countries included in the study, the Central African Republic reported the highest infertility burden in 35- to 49-year-old women, and Nepal had the lowest. However, the trends over time highlight that the infertility burden is shifting from lower-income areas to wealthier countries, where women are more likely to delay marriage and motherhood.

This study also attempted to calculate – in theory – the lowest achievable infertility burden on a country based on its income, education and fertility rate. The results showed that certain affluent countries, such as Sweden and France, were furthest from their optimal frontier, with the biggest need to improve public health approaches. In contrast, certain lower-income nations such as Nepal and Mali were performing closest to their best achievable frontier.

The authors said their findings provide evidence for a need to restructure reproductive healthcare to reduce advanced-age infertility. They suggest implementing coordinated efforts such as investment in fertility treatment, promotion of family planning and global access to reproductive care.

'The rise in infertility associated with this age group cannot be addressed solely by expanding the range of assisted reproductive therapy options,' said Dr Rocío Núñez Calonge, coordinator of the Ethics Committee of the Spanish Fertility Society, who was not involved in the research. 'In countries such as Spain, it is also necessary to address the social factors that contribute to delayed motherhood, particularly those relating to work-life balance, economic stability and institutional support for early motherhood.'