Definition: Percentage of infants born prior to 37 weeks of gestation.
Data Source: California Dept. of Public Health, Center for Health Statistics, Birth Statistical Master Files; Centers for Disease Control & Prevention, Natality data on CDC WONDER; Martin et al. (2015), Births: Final Data for 2013. National Vital Statistics Reports, 64(1) (Mar. 2015).
Footnote: Calculated from date of last reported mensus. The county-level data reflect the mother's county of residence, not the county in which the birth occurred. LNE (Low Number Event) refers to data that have been suppressed because there were fewer than 20 preterm births. N/A means that data are not available. Data exclude infants for whom preterm birth information is missing.