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Oregon EPHT: Birth Outcomes Indicator

EPHT Reproductive Health and Birth Outcomes Indicators: Fertility, Sex Ratio, Prematurity, Growth Retardation and Mortality.

To see explanations, tables, graphs and maps for each measure, click on the measure name below.

  • Fertility – Total fertility rate.
  • Sex Ratio – Male to female ratio at birth.
  • Prematurity – Preterm birth percentage; Very preterm birth percentage; Very low birth weight birth percentage.
  • Growth Retardation – Low birthweight percentage.
  • Mortality – Infant mortality rate; neonatal rate; postneonatal rate, perinatal mortality rate.

Or, view the full EPHT report on  Reproductive Health and Birth Outcomes (pdf). 

Information about Indicators: Indicators provide information about a population’s health status with respect to environmental factors when clear measurable links are not available. As part of the nationwide EPHT network implementation, work groups developed indicators and measures. Guidelines were established for the collection of data and the calculation of measures in a nationally-consistent way (called Nationally Consistent Data and Measures, or NCDMs).

EPHT intends to enhance existing vital statistics surveillance data by creating reproductive and birth outcomes indicators that are more relevant for linking to environmental exposure and by gathering hazard data not currently being routinely collected by health surveillance systems. The Oregon EPHT program is tracking several reproductive and birth outcomes, including fertility, sex ratio, prematurity, growth retardation and infant mortality.

EPHT indicators were selected on the basis of several criteria: availability of data across states, accuracy and completeness of data, validity of the indicator (whether it represents what it is supposed to represent), and possible relevance to environmental hazards and exposures.

For more information about environmental health indicators from the CDC:

Data sources and calculations:  The vital statistics data used in the calculation of these measures were collected by the Oregon Health Authority Center for Health Statistics (CHS). CHS is responsible for registering, certifying, amending and issuing Oregon vital records. Oregon law requires that all vital events such as births, marriages, divorces and deaths be recorded and registered. These are the legal records documenting vital events. For more information, please visit their website:

Any rates with numerators less than five are suppressed. In Oregon, counts and rates are published in the Center for Health Statistics (CHS) annual reports. EPHT Network indicators may differ from the CHS reports because of variations in how the measures are defined and calculated.

In 1999, the Oregon Center for Health Statistics (CHS) developed the guidelines for using and releasing small numbers that have been followed in this report. These guidelines refer to two concerns related to small numbers: releasing small numbers may result in a potential confidentiality violation; and using small numbers to calculate rates or percentages may not produce reliable information and can lead to misinterpretation of the data.

Counts, percentages and rates are only included in this report if the population denominator is greater than 50. In cases where the denominator population is greater than 50 but the numerator (number of events) is less than five, the number can be released but with the warning that rates or percentages calculated with less than five events may be unreliable. In this report EPHT has used a more conservative reliability guideline of 10 events. Numerators of less than 10 are identified as potentially unreliable. Data aggregated over three or more years are not subject to suppression.