Year | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 |
---|---|---|---|---|---|---|---|---|---|---|
Number of births | 554,689 | 546,201 | 524,058 | 508,124 | 500,367 | 502,124 | 492,921 | 500,404 | 490,383 | 487,818 |
Number of preterm births | 50,108 | 48,796 | 45,394 | 42,909 | 42,080 | 41,839 | 40,885 | 40,767 | 40,947 | 41,555 |
Percentage of preterm births | 9.0 | 8.9 | 8.7 | 8.4 | 8.4 | 8.3 | 8.3 | 8.2 | 8.4 | 8.5 |
Variable | ||||||||||
Maternal age (years) | ||||||||||
< 20 | 9.1 | 8.8 | 8.4 | 8.2 | 8.2 | 8.1 | 8.0 | 8.0 | 8.0 | 8.3 |
20–24 | 8.1 | 8.0 | 7.7 | 7.6 | 7.4 | 7.4 | 7.4 | 7.1 | 7.5 | 7.7 |
25–29 | 8.2 | 8.1 | 7.8 | 7.6 | 7.6 | 7.6 | 7.6 | 7.3 | 7.5 | 7.7 |
30–34 | 9.0 | 8.9 | 8.6 | 8.4 | 8.4 | 8.3 | 8.1 | 8.0 | 8.2 | 8.2 |
35–39 | 10.7 | 10.6 | 10.4 | 10.0 | 10.0 | 9.7 | 9.7 | 9.5 | 9.7 | 9.9 |
40–54 | 14.2 | 14.4 | 14.1 | 13.5 | 13.6 | 13.3 | 13.2 | 13.2 | 13.5 | 13.6 |
Maternal race and ethnicity | ||||||||||
Hispanic | 8.6 | 8.4 | 8.2 | 8.0 | 8.1 | 8.1 | 8.2 | 8.2 | 8.4 | 8.7 |
Whitea | 9.0 | 8.8 | 8.5 | 8.2 | 8.0 | 7.6 | 7.7 | 7.3 | 7.5 | 7.6 |
Asianb | 8.8 | 8.8 | 8.8 | 8.3 | 8.4 | 8.3 | 8.0 | 7.5 | 7.8 | 8.1 |
Pacific Islanderc | 10.7 | 10.3 | 9.4 | 10.3 | 8.6 | 8.8 | 8.9 | 9.1 | 10.8 | 9.6 |
African American | 12.7 | 13.0 | 12.3 | 12.2 | 11.7 | 11.9 | 11.6 | 11.9 | 11.7 | 11.4 |
Multiple race | 9.8 | 9.1 | 9.2 | 9.1 | 8.6 | 9.1 | 8.7 | 9.0 | 8.9 | 9.3 |
American Indiand | 10.4 | 10.6 | 9.3 | 10.0 | 8.8 | 8.8 | 10.0 | 8.9 | 10.1 | 10.3 |
Other/unknowne | 12.8 | 13.0 | 11.7 | 12.2 | 12.0 | 11.3 | 11.1 | 11.6 | 10.9 | 10.5 |
Maternal education level | ||||||||||
Less than high school diploma | 8.8 | 8.7 | 8.5 | 8.3 | 8.4 | 8.4 | 8.7 | 9.0 | 9.3 | 9.5 |
High school diploma | 8.9 | 9.0 | 8.5 | 8.4 | 8.4 | 8.2 | 8.2 | 8.1 | 8.3 | 8.6 |
Some college or associate degree | 9.4 | 9.1 | 8.8 | 8.8 | 8.7 | 8.5 | 8.5 | 8.3 | 8.5 | 8.6 |
Bachelor’s degree or higher | 8.9 | 8.7 | 8.5 | 8.0 | 7.9 | 7.9 | 7.6 | 7.3 | 7.5 | 7.6 |
Unknown | 10.9 | 11.3 | 10.6 | 10.5 | 10.4 | 10.2 | 10.5 | 10.2 | 9.8 | 10.0 |
Maternal nativity | ||||||||||
Foreign-born | 8.2 | 8.2 | 8.0 | 7.8 | 8.0 | 7.9 | 7.9 | 7.8 | 8.1 | 8.4 |
United States-born | 9.7 | 9.5 | 9.1 | 8.9 | 8.7 | 8.6 | 8.5 | 8.3 | 8.5 | 8.6 |
Maternal demographic region | ||||||||||
Central Coast | 8.1 | 8.1 | 7.7 | 7.7 | 7.7 | 7.4 | 7.8 | 7.4 | 7.9 | 7.9 |
Greater Bay Area | 8.5 | 8.6 | 8.6 | 8.4 | 8.1 | 8.4 | 8.2 | 7.9 | 8.1 | 8.3 |
Inland Empire | 9.5 | 9.0 | 8.9 | 8.6 | 8.4 | 8.7 | 8.5 | 8.3 | 8.5 | 8.8 |
Los Angeles County | 9.3 | 9.3 | 8.8 | 8.6 | 8.7 | 8.5 | 8.5 | 8.4 | 8.7 | 8.8 |
Northern and Sierra | 8.4 | 8.0 | 7.6 | 7.4 | 7.6 | 7.5 | 7.7 | 7.4 | 8.0 | 8.1 |
Orange County | 8.7 | 8.3 | 8.5 | 8.1 | 8.2 | 7.8 | 7.6 | 7.3 | 7.5 | 7.9 |
Sacramento area | 8.8 | 8.5 | 8.3 | 8.2 | 8.1 | 8.0 | 7.9 | 8.1 | 8.0 | 8.1 |
San Diego area | 9.5 | 9.0 | 9.0 | 8.4 | 8.4 | 8.3 | 8.1 | 8.2 | 8.0 | 8.4 |
San Joaquin Valley | 9.4 | 9.7 | 9.1 | 8.9 | 9.0 | 8.8 | 8.9 | 8.8 | 9.0 | 9.0 |
Source of prenatal care payment | ||||||||||
Private | 9.2 | 9.0 | 8.8 | 8.7 | 8.5 | 8.4 | 8.2 | 8.1 | 8.2 | 8.3 |
Medi-Cal | 8.7 | 8.6 | 8.3 | 8.1 | 8.1 | 8.2 | 8.3 | 8.2 | 8.5 | 8.7 |
WIC Participation | ||||||||||
No | 9.5 | 9.4 | 9.1 | 8.9 | 8.7 | 8.6 | 8.4 | 8.1 | 8.3 | 8.4 |
Yes | 8.6 | 8.5 | 8.3 | 8.0 | 8.2 | 8.1 | 8.2 | 8.2 | 8.4 | 8.6 |
First trimester prenatal care initiation | ||||||||||
No | 9.1 | 8.6 | 8.3 | 8.3 | 8.2 | 8.2 | 8.2 | 8.1 | 8.2 | 8.5 |
Yes | 8.9 | 8.9 | 8.6 | 8.4 | 8.4 | 8.3 | 8.2 | 8.1 | 8.3 | 8.4 |
Parity | ||||||||||
Primiparous | 8.4 | 8.2 | 8.0 | 7.8 | 7.7 | 7.7 | 7.7 | 7.4 | 7.7 | 7.8 |
Multiparous (2–5) | 9.3 | 9.2 | 8.9 | 8.7 | 8.6 | 8.5 | 8.4 | 8.4 | 8.5 | 8.7 |
Multiparous (6–12) | 14.9 | 15.2 | 15.0 | 14.6 | 13.9 | 14.6 | 14.7 | 15.3 | 15.3 | 15.6 |
Plurality | ||||||||||
Singleton births | 8.0 | 7.9 | 7.5 | 7.4 | 7.3 | 7.3 | 7.2 | 7.1 | 7.3 | 7.5 |
Multiple births | 60.9 | 59.2 | 59.0 | 57.4 | 57.4 | 56.0 | 55.0 | 54.4 | 55.8 | 56.8 |
Maternal smoking during both first and second trimesters | ||||||||||
No | 8.9 | 8.8 | 8.6 | 8.4 | 8.3 | 8.2 | 8.2 | 8.1 | 8.2 | 8.4 |
Yes | 15.7 | 15.0 | 14.6 | 14.2 | 14.8 | 15.6 | 16.4 | 15.5 | 16.9 | 17.9 |
Prepregnancy body mass index (kg/m2) | ||||||||||
Underweight (≤18.5) | 9.7 | 10.0 | 9.4 | 9.0 | 8.9 | 8.8 | 8.6 | 8.5 | 8.4 | 8.7 |
Normal (18.5–24.9) | 8.5 | 8.4 | 8.1 | 7.9 | 7.9 | 7.7 | 7.7 | 7.4 | 7.5 | 7.7 |
Overweight (25.0–29.9) | 8.8 | 8.5 | 8.3 | 8.1 | 8.3 | 8.2 | 8.1 | 8.1 | 8.2 | 8.6 |
Obese I (30.0–34.9) | 9.6 | 9.3 | 9.1 | 9.0 | 8.9 | 8.8 | 8.9 | 9.0 | 9.3 | 9.3 |
Obese II (35.0–39.9) | 10.1 | 10.1 | 10.4 | 9.4 | 9.1 | 10.1 | 9.4 | 9.6 | 10.1 | 10.1 |
Obese III (≥ 40) | 10.8 | 11.2 | 10.0 | 11.2 | 10.3 | 10.1 | 10.4 | 10.0 | 10.6 | 10.4 |