Figure 2: Low Birth Weight Rate by Race/Ethnicity, King County

Figure 3: Low Birth Weight Rate by Health Planning Area, King County

Figure 1: Low Birth Weight out of All Births and Singleton Births Only, King County, 1994-2003

Figures:  
• Figure 2: Low Birth Weight Rate by Race/Ethnicity, King County  – 
• Figure 3: Low Birth Weight Rate by Health Planning Area, King County  – 
• Figure 1: Low Birth Weight out of All Births and Singleton Births Only, King County, 1994-2003

Data Discussion

The Indicator Defined

Low Birth Weight Rate is the percentage of infants weighing less than 2500 grams (5.5lbs) at birth in King County. The weight of an infant at the time of birth is an important predictor of infant survival. Low birth weight babies have a greater risk of dying in their first year of life. In addition, they are more likely to have health problems throughout their lives.

Data Interpretation/Evaluation

Low birth weight is an important risk factor of infant mortality, childhood developmental disorders and, later, of adult chronic medical conditions such as diabetes, hypertension and heart disease. The rate of low birth rates in King County increased from 1999 to 2004. In 2004, 6.4 percent of infants born in King County were low birth weight including 1,455 low birth weight infants (Figure 1). This was higher than the Washington state rate of 6.2 percent and higher than the National Healthy People 2010 goal of 5.0 percent. In comparison to 15 major metropoitan U.S. counties, King County has the 13th lowest rate of low birth weight.

African American women in King County are twice as likely to have a low birth weight infant and American Indian/Alaska Native and Asian/Pacific Islander women still have significantly higher low birth weight rates compared to white and Latina/Hispanic women (Figure 2).

From 1994 to 2003, a significant increase in rates of low birth weight occurred in the East, North and South Regions of King County while Seattle showed no significant change in the rate of low birth weight. East Region had a significantly lower rate of low birth weight from 1999-2003 than Seattle or the South Region.

In past years, high poverty neighborhoods consistently had significantly higher rates of low birth weight than low poverty neighborhoods. From 1994-2003, low birth weight rates increased significantly in low poverty neighborhoods and in the past 5 years, from 1999-2003, low birth weight rates declined significantly in high poverty neighborhoods. This has resulted in no significant difference in rates of low birth weight by neighborhood poverty level. Central Seattle, Beacon Hill/Georgetown/South Park, and White Center/Boulevard Park Health Planning Areas tend to have the highest rates of low birth weight in King County. The lowest rates of low birth weight in King County were in the Fremont/Greenlake and Issaquah/Sammamish Health Planning Areas (Figure 3).

Mothers less than 18 years of age and 40 years or older had significantly higher rates of low birth weight compared to women between the ages of 18 and 39. Mothers 25-34 years of age had the lowest rates of low birth weight.

Data Source and Limitations

Data comes from King Count Community Health Indicators, from Public Health Seattle and King County.  Their original source is Washington State Department of Public Health, Center for Health Statistics, Birth Certificate Data.

Data discussion was excerpted by Sustainable Seattle from Health of King County Report 2006 Report by Seattle King County Public Health. 

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