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Assessing birth outcomes among populations
For many years, researchers have used birth outcomes
as one of the main measures of health in populations. This may be due to
the importance of pregnant women, infants, and children in our society, as well
as their comparatively vulnerable health status. But undoubtedly, part of
the reason is that birth outcomes are relatively easy to measure.
Any particular pregnancy may be complicated by factors
such as an infection or an abnormality in the infant's development. However, the simplest way
to describe birth outcomes for a population is to count the number of births where the infant was born either too
early (less than 37 weeks) or too small (less than 2,500 grams, about 5.5
pounds). These outcomes are called preterm birth and
low birthweight. Infants that are born preterm or with a low birthweight are at higher risk of dying in the first year of life and of having developmental problems throughout life.
Many factors can influence preterm birth and low
birthweight. These include maternal smoking, nutritional status, medical care,
and level of stress and/or social support. Scientists are now
learning that exposure to pollution during pregnancy can also have an effect.
Understanding the influences on birth outcomes is important, as preventing
preterm birth and low birthweight is more humane and less costly than treating
critically ill infants after they are born.
Snapshot of Findings
In 2001, the preterm birth rate for Alameda County was 8.5%. The TLBW rate
for Alameda County was
2.4%.
Black mothers were almost twice as likely as mothers of any other
race/ethnicity to have preterm births.
Non-white mothers were more likely than white mothers to have TLBW
births.
Mothers living in lower income neighborhoods were more likely to have preterm and TLBW
births.
Birth outcomes analysis
In this project, we used Vital Statistics data to look at
singleton preterm and term
low birthweight (TLBW) births in Alameda County for 2001. TLBW occurs
when the infant is born full term (37 or more weeks), but still weighs less
than 2,500 grams.
It is important to distinguish when the births
occurred because the most common cause of low birthweight is the infant
being born too soon (preterm) and not having enough time to finish growing. TLBW
indicates that there was something that interfered with growth during
pregnancy. Since TLBW births are not accounted for in studies on
preterm birth, scientists are increasingly examining them as a separate
outcome.
Through the pilot project, we were able to create maps of preterm birth and TLBW
births that show community-level rates and "hot-spots" throughout the county.
We also looked at rates of preterm birth and TLBW births among different groups.
 Click
below to see birth outcomes findings:
Preterm birth disparities
Preterm birth map
and tables
Term low birthweight
disparities
Term low birthweight map
and tables
See Associations
Findings on traffic pollution and birth outcomes
Questions about birth outcomes or these results? Click below:
FAQs on
birth outcomes and results
Overview of pilot project
data and methods
Additional resources on
birth outcomes
Michelle Wong, MPH
mwong@dhs.ca.gov
Return to
the pilot project findings page
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