Fertility and Infertility in Birth Outcomes: Measures and Data
Why is infertility an environmental public health problem?Estimates from the CDC’s National Survey of Family Growth indicate that 12% of U.S. couples experienced impaired fertility in 2002. In the same year, roughly 7.3 million women between ages 15-44 received some kind of infertility service.
Infertility may be caused by factors related to the male or female partner. In a large percentage of cases, infertility is due to a combination of factors from both partners, and in roughly 10% of cases the reason for infertility is unexplained. Older age is strongly associated with impaired fertility, as are some pre-existing medical conditions, including sexually transmitted diseases and other infections among both females and males.
However, delayed childbearing and medical conditions don’t fully account for trends in male and female infertility. A range of other risk factors may contribute to a portion of infertility cases, including stress, poor nutrition, and smoking. Some environmental contaminants may have the potential to influence infertility. Research suggests that certain chemicals can affect women’s menstruation and ovulation patterns. Among men, studies have shown that higher exposures to some toxics can lead to low sperm counts, sperm damage, or sperm abnormalities. More research is needed to understand how contaminants may affect fertility.
WTN maintains a list of recent publications that discuss measures of maternal and child health and the scientific evidence concerning the impact of environmental hazards on birth outcomes, including fertility. NIOSH provides information about the effects of certain occupational exposures on reproductive health in men and women. Much more research needs to be done to understand how contaminants may affect human fertility.
How are fertility and infertility defined and tracked?Fertility rates measure the number of births among all women aged 15-44 years in the population or among women of specific age groups. Fertility rates are calculated from birth certificate data and population data. Birth data are collected through the Vital Registration System at the Department of Health (DOH) Center for Health Statistics, and are reported by the State Registrar to CDC National Center for Health Statistics.
By contrast, measuring infertility in the population requires different data sources and a different calculation. Infertility is generally defined as the inability to achieve pregnancy despite having frequent, unprotected sex for one year. The population-based "National Survey of Family Growth" conducted by CDC National Center for Health Statistics is the primary system for collecting data that provide periodic estimates of infertility in the U.S.
What is being done to prevent the risks that lead to infertility?Although not all risks for infertility are preventable, an environment that promotes a safe and healthy lifestyle provides optimal conditions for conception and a healthy pregnancy. The Department of Health carries out many activities to promote the health and well being of Washington residents, including smoking cessation, nutrition and physical activity promotion, STD prevention work, and guidance for healthy fish choices. The Department of Labor and Industry carries out programs to protect working men and women from exposure to contaminants that could impact reproductive health. Find out more about strategies for creating Healthy Communities.
More Information on Specific Birth Outcomes