Variable | Crude odds ratio | Adjusted odds ratio | ||
---|---|---|---|---|
OR (95% CI) | p-valuea | OR (95% CI) | p-valuea | |
Birth year | ||||
 2008 | 0.99 (0.98–1.00) | 0.148 | 0.99 (0.97–1.00) | 0.110 |
 2009 | 0.95 (0.93–0.96) | <.001 | 0.94 (0.92–0.96) | <.001 |
 2010 | 0.93 (0.91–0.94) | <.001 | 0.92 (0.91–0.94) | <.001 |
 2011 | 0.92 (0.90–0.93) | <.001 | 0.91 (0.90–0.93) | <.001 |
 2012 | 0.92 (0.90–0.93) | <.001 | 0.91 (0.90–0.93) | <.001 |
 2013 | 0.91 (0.89–0.92) | <.001 | 0.90 (0.89–0.92) | <.001 |
 2014 | 0.89 (0.87–0.90) | <.001 | 0.89 (0.87–0.90) | <.001 |
 2015 | 0.92 (0.90–0.93) | <.001 | 0.91 (0.89–0.93) | <.001 |
 2016 | 0.94 (0.92–0.95) | <.001 | 0.93 (0.91–0.94) | <.001 |
 2007 | Refb |  | Refb |  |
Maternal age (years) | ||||
  < 20 | 1.16 (1.15–1.18) | <.001 | 1.07 (1.05–1.09) | <.001 |
 25–29 | 0.97 (0.96–0.98) | <.001 | 1.08 (1.07–1.10) | <.001 |
 30–34 | 1.01 (1.00–1.02) | 0.015 | 1.24 (1.22–1.26) | <.001 |
 35–39 | 1.20 (1.19–1.22) | <.001 | 1.51 (1.49–1.54) | <.001 |
 40–54 | 1.54 (1.52–1.57) | <.001 | 1.92 (1.88–1.96) | <.001 |
 20–24 (ref) | Refb |  | Refb |  |
Maternal race/ethnicity | ||||
 African American | 1.77 (1.74–1.79) | <.001 | 1.64 (1.61–1.67) | <.001 |
 American Indian | 1.46 (1.39–1.54) | <.001 | 1.26 (1.18–1.35) | <.001 |
 Asian | 1.16 (1.14–1.17) | <.001 | 1.40 (1.38–1.42) | <.001 |
 Hispanic | 1.23 (1.22–1.24) | <.001 | 1.22 (1.21–1.24) | <.001 |
 Multiple Race | 1.26 (1.23–1.29) | <.001 | 1.23 (1.20–1.26) | <.001 |
 Other Unknown | 1.35 (1.32–1.38) | <.001 | 1.26 (1.22–1.30) | <.001 |
 Pacific Islander | 1.48 (1.41–1.55) | <.001 | 1.43 (1.35–1.51) | <.001 |
 White (ref) | Refb |  | Refb |  |
Maternal education | ||||
  < High school | 1.37 (1.36–1.38) | <.001 | 1.35 (1.33–1.38) | <.001 |
 High school diploma | 1.28 (1.27–1.29) | <.001 | 1.30 (1.28–1.31) | <.001 |
 Some college/associate degree | 1.27 (1.26–1.29) | <.001 | 1.28 (1.26–1.30) | <.001 |
 Unknown | 1.39 (1.36–1.41) | <.001 | 1.30 (1.27–1.34) | <.001 |
 Bachelor’s degree or higher (ref) | Refb |  | Refb |  |
Maternal nativity | ||||
 United States-born | 1.08 (1.07–1.08) | <.001 | 1.15 (1.14–1.16) | <.0001 |
 Foreign-born (ref) | Refb |  | Refb |  |
Maternal demographic region | ||||
 Central Coast | 0.97 (0.95–1.00) | 0.023 | 1.01 (0.98–1.04) | 0.621 |
 Greater Bay Area | 1.03 (1.00–1.05) | 0.022 | 1.04 (1.01–1.06) | 0.007 |
 Inland Empire | 1.14 (1.11–1.16) | <.001 | 1.13 (1.10–1.16) | <.001 |
 Los Angeles County | 1.13 (1.11–1.15) | <.001 | 1.12 (1.09–1.14) | <.001 |
 Orange County | 0.99 (0.97–1.02) | 0.493 | 1.05 (1.02–1.08) | 0.001 |
 Sacramento Area | 1.03 (1.01–1.06) | 0.016 | 1.05 (1.02–1.08) | 0.001 |
 San Diego Area | 1.07 (1.04–1.09) | <.001 | 1.13 (1.10–1.16) | <.001 |
 San Joaquin Valley | 1.21 (1.18–1.24) | <.001 | 1.18 (1.15–1.22) | <.001 |
 Northern and Sierra (ref) | Refb |  | Refb |  |
Source of prenatal care payment | ||||
 Medi-Cal (Public) | 1.13 (1.12–1.14) | <.001 | 1.12 (1.11–1.13) | <.001 |
 Private insurance (ref) | Refb |  | Refb |  |
cWIC participation | ||||
 No | 0.95 (0.94–0.96) | <.001 | 1.13 (1.12–1.14) | <.001 |
 Yes (ref) | Refb |  | Refb |  |
First trimester prenatal care initiation | ||||
 No | 1.08 (1.07–1.09) | <.001 | 1.07 (1.06–1.09) | <.001 |
 Yes (ref) | Refb |  | Refb |  |
Parity | ||||
 Primiparous | 1.03 (1.02–1.04) | <.001 | 1.16 (1.15–1.17) | <.001 |
 Multiparous 6–12 | 1.84 (1.80–1.88) | <.001 | 1.35 (1.32–1.39) | <.001 |
 Multiparous 2–5 (ref) | Refb |  | Refb |  |
Maternal smoking | ||||
 Yes | 1.85 (1.81–1.89) | <.001 | 1.57 (1.53–1.62) | <.001 |
 No (ref) | Refb |  | Refb |  |
Maternal prepregnancy body mass index (kg/m2) | ||||
 Underweight, < 18.5 | 1.23 (1.20–1.25) | <.001 | 1.23 (1.20–1.25) | <.001 |
 Overweight, 25.0–29.9 | 1.09 (1.08–1.09) | <.001 | 1.06 (1.05–1.07) | <.001 |
 Obese I–30.0–34.9 | 1.22 (1.21–1.23) | <.001 | 1.16 (1.15–1.17) | <.001 |
 Obese II, 35.0–39.9 | 1.31 (1.29–1.33) | <.001 | 1.24 (1.22–1.26) | <.001 |
 Obese III, ≥ 40 | 1.44 (1.42–1.47) | <.001 | 1.33 (1.30–1.36) | <.001 |
 Normal, 18.5–24.9 (ref) | Refb |  | Refb |  |