Despite a worldwide increase in obesity and type 2 diabetes, metabolic conditions that affect fertility, infertility rates appear to be holding steady after 20 years, according to the World Health Organization (WHO). Data collected from nearly 200 countries shows minimal change considered statistically insignificant.
In 2010 about 48.5 million couples suffered infertility, according to the WHO. Infertility was defined as not being able to conceive after five years of trying. In a clinical sense, doctors typically diagnose infertility after a woman in unable to give birth for a period of 12 consecutive months. In total about 2% of women ages 19 to 44 were unable to give birth to their first child and about 11% of women were unable to give birth to a subsequent child after previous birth.
The only country that showed marked improvement was sub-Saharan Africa. Dr. Gretchen Stevens, lead author of the study, claimed improved healthcare for patients with HIV may have caused the marked drop. Without proper treatment HIV can lead to infertility. Improvements in medical care for pregnant women may have also been a contributing factor.
There have been reports of increased infertility rates associated with an increasing number of women choosing to wait longer to attempt pregnancy and environmental effect on sperm, but the WHO study does not support claims of increased infertility.
The difference in medical definition of infertility is a topic of interest to some in the medical community. Five years of attempting to achieve live birth is a long time to wait before designating infertility. Authors claims the five-year period was used to allow for couple status, birth data collection, use of contraception and couples fertility preference. Rarely included in the surveys were questions about how long women had been trying to achieve live birth or information on terminated pregnancies and miscarriages.
Source: Maya N. Mascarenhas, Seth R. Flaxman, Ties Boerma, Sheryl Vanderpoel, Gretchen A. Stevens. National, Regional, and Global Trends in Infertility Prevalence Since 1990: A Systematic Analysis of 277 Health Surveys.