Reproductive Health Indicator:  Fertility

Measure: Total Fertility Rate

According to data from the National Survey of Family Growth, 12% of U.S. couples had impaired fertility in 2002, up 20% from 1995. Approximately 10% of problems with fertility are unknown and environmental contaminants including endocrine disruptors have been hypothesized as major contributors. Environmental contamination can have multi-generational impacts on reproduction that need to be studied and tracked long term.

It has been suspected that low-level exposures to a number of compounds, such as phthalates, polychlorinated biphenyls (PCBs), dioxin, pesticides and other compounds may be affecting human fertility. There is documented evidence that specific exposures to compounds such as DBCP in the workplace have affected male fertility. 

It has been proposed that two male reproductive birth defects, hypospadias and cryptorchidism, along with testicular cancer, are part of a syndrome called “testicular dysgenesis syndrome,” which has been hypothesized to be related to exposure to endocrine disrupting compounds in the environment.

Fertility trends provide basic descriptive data that may supply clues about changes that may be influenced by environmental risk factors. As more is learned about the link between adverse exposures and fertility, these rates could provide important background information about how fertility varies geographically in relation to changes in environmental and health risk factors and how it has varied over time within the state and across the United States.

The fertility measure is influenced by social/demographic choices for reproduction, maternal age, parity and social class as well as by contraception use and fertility treatments leading to multiple births. Because these factors lead to significant variations in overall fertility across populations and geographic locations, social and demographic factors would need to be controlled for to examine any environmental effects on total fertility.

Oregon EPHT fertility rate calculations are based on annual census estimates of the population of resident Oregon women of reproductive age (10-49 years old). The EPHT total fertility rate is the lifetime expected number of births to a hypothetical woman if she experienced the total of the age-specific live birth rates that were observed in a given year. For example, in Oregon the 2000 total fertility rate was 2.0. That is the average number of children that would be expected to be born to a woman over her lifetime if she were to experience the current age-specific rates throughout her lifetime and she were to survive from birth through the end of her reproductive life. This can also be represented as a rate per 1,000 women instead of a rate per woman i. e., as 2000.  

The table, graph and map below present the annual total fertility rate per woman of reproductive age from 2000-2006, by state and county. The total fertility rate adjusts for age-specific differences in fertility allowing for comparisons of rates over time and between geographical areas,

Southwest Oregon and scattered counties in the north and central regions had the lowest fertility rates. The eastern and north central area of the state had the highest fertility rates. The smallest and largest percentages of total fertility among the youngest women were both in rural counties (3 and 16 percent in Wallowa and Jefferson counties, respectively). In the oldest age group, the five lowest percentages of total fertility (1 percent) were in rural counties without college populations (Sherman, Wallowa, Baker, Grant, Coos) and the highest (3 percent) are in counties with large college and urban populations (Benton and Multnomah counties).

Table 1: Annual total fertility rate for women of reproductive age (10 – 54 years) by Oregon county and year, for 2000 to 2006.  

Graph 1: Total fertility fate by Oregon county, summarized for 2000 to 2006.  

Map 1: Total fertility rates, summarized from 2000 to 2006, by county. 

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Table 1: Annual total fertility rate for women of reproductive age (10 – 54 years) by Oregon county and year, for 2000 to 2006.

Rates based on less than 10 births are considered unstable and marked with an asterisk (*).

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Graph 1: Total fertility fate by Oregon county, summarized for 2000 to 2006.

The graph shows 95% Confidence Intervals (CI). If the entire CI of a county is above or below the Oregon rate (shown as a dotted vertical line), then the total fertility rate of that county is significantly higher or lower, respectively, than the Oregon rate.

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Map 1: Total fertility rates, summarized from 2000 to 2006, by county.

Counties in different categories differ significantly in their total fertility rates.

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