Global female infertility rates surge, hitting women in their late 30s hardest

A sweeping new analysis reveals that the burden of female infertility has soared over the past three decades, with age-standardized rates rising and women in their late 30s facing the highest risk worldwide.

Study: Global, regional, and national burden of female infertility and trends from 1990 to 2021 with projections to 2050 based on the GBD 2021 analysis. Image Credit: Taimit / Shutterstock

In a recent article published in the journal Scientific Reports, researchers assessed global trends in female infertility by analyzing changes in prevalence across sociodemographic levels, regions, and ages between 1990 and 2021 and making predictions for the coming years.

Their findings indicate that more than 110 million women were affected by female infertility in 2021, representing an increase of 84% since 1990, with women between 35 and 39 years old being most affected.

Background

The World Health Organization (WHO) defines female infertility as occurring when an individual cannot conceive after having regular and unprotected sex for 12 months. It is important to note that the Global Burden of Disease (GBD) 2021 study, on which this research is based, uses a different definition: primary female infertility is characterized by the failure to conceive a child after 5 years of unprotected intercourse, and secondary infertility was identified in couples who desired a child and had been together for over 5 years without using contraception since their last live birth. This condition can be classified as primary or secondary, with varying prevalence rates.

In the U.S., between 7% and 16% (the paper states 7-15.5%) of reproductive-age women are affected. Globally, one in seven couples living in developed nations and 25% of those living in developing countries face infertility, and in countries like China, 15% of women of reproductive age are impacted.

Assisted reproductive treatments like in-vitro fertilization (IVF) incur high costs that range from over $12,000 per cycle in the U.S. to under $4,000 in Japan, based on 2006 United States dollars.

The causes of infertility are multifactorial, with fallopian tube blockages, ovulatory disorders, hormonal imbalances, genetic issues, epigenetic mechanisms potentially linked to environmental pollution, and other environmental factors all contributing. Infertility is also associated with elevated risks for gynecological cancers and chronic conditions like endometriosis, which is linked to asthma, autoimmune diseases, and cardiovascular problems.

Despite its broad health and social implications, infertility research remains limited. Prior studies show regional differences in infertility types and trends, including increases in polycystic ovary syndrome (PCOS)-related infertility and complex regional patterns in endometriosis burden.

About the study

In this study, researchers used the Global Burden of Disease (GBD) dataset to present a comprehensive, age- and region-specific analysis of female infertility prevalence and disability-adjusted life years (DALYs) from 1990 to 2021, with projections to 2050 to inform global health strategies and policy development.

The GBD database compiles health-related data from household surveys, demographic records, and other validated sources. For infertility, DALYs were calculated based solely on years lived with disability (YLD), as infertility is non-fatal.

The analysis included 204 countries and territories grouped into five sociodemographic index (SDI) categories. Cluster analysis was employed to identify regional patterns of change, for instance, noting significant increases in Andean Latin America and decreases in regions like Oceania.

Projections from 2022 to 2050 were made using an autoregressive integrated moving average (ARIMA) model, estimating future prevalence, DALYs, and age-standardized rates. Correlation analysis was used to assess relationships between socioeconomic variables, such as the Human Development Index (HDI), and infertility prevalence.

Key findings

In 2021, female infertility affected approximately 110 million women worldwide, with an age-standardized prevalence rate (ASPR) of 1,367.4 for every 100,000 and over 601,000 associated DALYs.

Women between 35 and 39 experienced the highest burden, with age-standardized rates about 1.2 times higher than those between 30 and 34. The burden varied by region and SDI level, with middle SDI regions reporting the highest case numbers, while high-middle SDI regions had the highest standardized rates.

Asia recorded the largest absolute burden, especially China and India. East Asia had the highest age-standardized rates, while countries like Australia and New Zealand reported the lowest.

Regarding temporal trends by SDI level, the age-standardized rates (ASR) in low and low-middle-SDI regions initially displayed a decrease, followed by a sharp increase starting around 2010, resulting in an overall upward trend. High SDI regions showed a slow increase followed by a decreasing trend in ASR.

The paper also notes that when looking at the relationship between ASR and SDI level at a point in time (rather than over time), territories with an SDI under 0.50 showed predominantly stable or slightly decreasing ASR, those with SDIs between 0.50 and 0.75 showed mild fluctuations in ASR, and regions with an SDI above 0.75 experienced a rapid decline in ASR.

Furthermore, a statistically significant positive association was found between the Estimated Annual Percent Change (EAPC) in infertility rates and the Human Development Index (HDI), indicating that in countries with high HDI, the incidence of female infertility increased in 2021 but showed a slowing trend when HDI exceeded 0.8.

Between 1990 and 2021, prevalence cases rose by 84.4%, and DALYs increased by 84.4%. Age-specific analysis showed a sharp rise in infertility among women between 30 and 34. While high-SDI regions saw eventual declines in their ASR trends over time, low- and middle-SDI areas faced sharp increases in their ASR after 2010.

Although the global number of women affected by infertility and total DALYs are projected to decline by 2050, the ASPR and DALYs standardized by age will continue to rise. This divergence is driven by population aging, increased infertility risk factors, including potential epigenetic impacts of industrial pollutants, and better diagnostics leading to higher detection rates.

Conclusions

Female infertility remains a substantial global health issue, affecting over 9% of women of reproductive age, with a growing prevalence and burden between 1990 and 2021. Factors like delayed childbearing, urbanization, industrial pollution, and potential epigenetic changes likely contribute to the observed trends.

Projections suggest a decreasing number of infertility cases and DALYs but an increasing ASPR, likely due to aging populations, lifestyle shifts, and greater awareness and diagnosis. Regional disparities, such as rising burdens in Andean Latin America and improvements in areas like Oceania, highlight the need for targeted interventions. Socioeconomic development, high-risk behaviors, and environmental exposures continue to shape fertility trends.

A major strength of this study is its global scope, leveraging extensive data. However, limitations include inconsistent data quality across countries and the lack of granular, patient-level details. Despite declining case numbers, female infertility remains a growing burden requiring targeted prevention, early screening, and enhanced reproductive healthcare policies.