|National, Regional, and Global Trends in Infertility Prevalence Since 1990: A Systematic Analysis of 277 Health Surveys|
||Maya N. Mascarenhas, Seth R. Flaxman, Ties Boerma, Sheryl Vanderpoel, and Gretchen A. Stevens
||PLOS Medicine, 9(12): e1001356; DOI: 10.1371/journal.pmed.1001356
More than one region
Global, regional, and national estimates of prevalence of and tends in infertility are needed to target prevention and treatment efforts. By applying a consistent algorithm to demographic and reproductive surveys available from developed and developing countries, we estimate infertility prevalence and trends, 1990 to 2010, by country and region.
Methods and Findings
We accessed and analyzed household survey data from 277 demographic and reproductive health surveys using a consistent algorithm to calculate infertility. We used a demographic infertility measure with live birth as the outcome and a 5-y exposure period based on union status, contraceptive use, and desire for a child. We corrected for biases arising from the use of incomplete information on past union status and contraceptive use. We used a Bayesian hierarchical model to estimate prevalence of and trends in infertility in 190 countries and territories. In 2010, among women 20–44 y of age who were exposed to the risk of pregnancy, 1.9% (95% uncertainty interval 1.7%, 2.2%) were unable to attain a live birth (primary infertility). Out of women who had had at least one live birth and were exposed to the risk of pregnancy, 10.5% (9.5%, 11.7%) were unable to have another child (secondary infertility). Infertility prevalence was highest in South Asia, Sub-Saharan Africa, North Africa/Middle East, and Central/Eastern Europe and Central Asia. Levels of infertility in 2010 were similar to those in 1990 in most world regions, apart from declines in primary and secondary infertility in Sub-Saharan Africa and primary infertility in South Asia (posterior probability [pp] =0.99). Although there were no statistically significant changes in the prevalence of infertility in most regions amongst women who were exposed to the risk of pregnancy, reduced child-seeking behavior resulted in a reduction of primary infertility among all women from 1.6% to 1.5% (pp?=?0.90) and a reduction of secondary infertility among all women from 3.9% to 3.0% (pp>0.99) from 1990 to 2010. Due to population growth, however, the absolute number of couples affected by infertility increased from 42.0 million (39.6 million, 44.8 million) in 1990 to 48.5 million (45.0 million, 52.6 million) in 2010. Limitations of the study include gaps in survey data for some countries and the use of proxies to determine exposure to pregnancy.
We analyzed demographic and reproductive household survey data to reveal global patterns and trends in infertility. Independent from population growth and worldwide declines in the preferred number of children, we found little evidence of changes in infertility over two decades, apart from in the regions of Sub-Saharan Africa and South Asia. Further research is needed to identify the etiological causes of these patterns and trends.
Please see later in the article for the Editors' Summary
Reproductive health is a priority global health area: the target for Millennium Development Goal 5B is to provide universal access to reproductive health by 2015. The indicators for monitoring progress in reaching this target are contraceptive prevalence rate, adolescent birth rate, antenatal care coverage, and the unmet need for family planning. Infertility, the inability to conceive after a prolonged period (the length of time varies in different definitions) of unprotected intercourse, is a critical but much neglected aspect of reproductive health. The inability to have children affects couples worldwide and causes emotional and psychological distress in both men and women. Many factors—including physiological, genetic, environmental, and social— contribute to infertility. According to the World Health Organization, infertility resulting from sexually transmitted diseases or reproductive tract infections is particularly problematic in Africa and Latin America.
Why Was This Study Done?
The researchers used a uniform measure of infertility that incorporated live birth as the outcome of interest (as this information is more commonly reported than pregnancies), a five-year “exposure period,” that is, a five-year period of being in an intimate relationship, not using contraceptives, and wanting a child (as the researchers calculated that this period was necessary to accommodate the time it takes to become pregnant and have a child, and to allow for incomplete information on frequency of unprotected intercourse). The researchers used a statistical model (Bayesian hierarchical model) to generate estimates for levels and trends of infertility in 190 countries over the time period 1990 to 2010 using information collected from national demographic and reproductive health surveys. The most data was available for South Asia and Sub-Saharan Africa.
What Did the Researchers Do and Find?
The researchers found that in 2010, 1.9% of women aged 20–44 years who wanted to have children were unable to have their first live birth (primary infertility), and 10.5% of women with a previous live birth were unable to have an additional live birth (secondary infertility). The researchers found that the levels of infertility were similar in 1990 and 2010, with only a slight overall decrease in primary infertility (0.1%, but with a more pronounced drop in Sub-Saharan Africa and South Asia) and a modest overall increase in secondary infertility (0.4%). Age affected infertility rates: the prevalence of primary infertility was higher among women aged 20–24 years than among older women. The age pattern was reversed and even more pronounced for secondary infertility. And primary infertility rates among women wanting children also varied by region, from 1.5% in Latin America and the Caribbean in 2010, to 2.6% in North Africa and the Middle East. With a few exceptions, global and country patterns of secondary infertility were similar to those of primary infertility.
What Do These Findings Mean?
These findings suggest that in 2010, an estimated 48.5 million couples worldwide were unable to have a child after five years. However, these findings also suggest that global levels of primary and secondary infertility hardly changed between 1990 and 2010. It is important to note that an infertility measure based on ability to become pregnant (rather than having a live birth—the outcome used in this study) may show different levels of infertility, and using an exposure period shorter than the five years used in this study would produce higher rates of infertility. However, because of the lack of widespread data collection on time to pregnancy, the methods used and results shown in this study provide useful insights into global, regional, and country patterns and trends in infertility.