Table 2. Multivariable Ordinal Regression Results for Preterm Birth and Logistic Regression for Infant Mortality Among Expectant Mothers Covered by Medicaid During Pregnancy, 2011-2017.
| Covariate | Adjusted OR (95% CI) | |
|---|---|---|
| Gestational Age Category (n = 10 005 357)a | Infant Mortality (n = 10 002 237)a | |
| Year of delivery (vs 2011) | ||
| 2012 | 0.98 (0.98-0.99) | 1.03 (1.00-1.07) |
| 2013 | 0.96 (0.96-0.97) | 1.02 (0.98-1.05) |
| 2014 | 0.97 (0.96-0.97) | 0.92 (0.89-0.96) |
| 2015 | 0.96 (0.95-0.96) | 1.04 (1.01-1.08) |
| 2016 | 0.97 (0.96-0.98) | 1.02 (0.99-1.06) |
| 2017 | 1.02 (1.01-1.02) | 1.02 (0.98-1.05) |
| Age at delivery (vs 25-29), y | ||
| <15 | 1.94 (1.86-2.02) | 1.13 (0.93-1.36) |
| 15-19 | 1.22 (1.21-1.23) | 1.18 (1.14-1.22) |
| 20-24 | 1.05 (1.04-1.05) | 1.10 (1.07-1.13) |
| 30-34 | 1.06 (1.05-1.06) | 0.94 (0.91-0.96) |
| 35-39 | 1.19 (1.18-1.20) | 0.94 (0.90-0.97) |
| 40-44 | 1.36 (1.34-1.38) | 1.16 (1.09-1.24) |
| ≥45 | 1.44 (1.37-1.51) | 1.50 (1.23-1.84) |
| Race/ethnicity (vs non-Hispanic white) | ||
| Hispanic | 1.05 (1.04-1.06) | 0.86 (0.84-0.88) |
| Non-Hispanic black | 1.43 (1.42-1.43) | 1.05 (1.03-1.08) |
| Non-Hispanic other | 1.09 (1.08-1.10) | 0.94 (0.90-0.98) |
| Educational attainment (vs <high school) | ||
| High school graduate | 0.93 (0.93-0.94) | 0.99 (0.96-1.01) |
| At least some college | 0.85 (0.85-0.86) | 0.92 (0.89-0.94) |
| Married (vs unmarried) | 0.87 (0.86-0.87) | 0.97 (0.95-0.99) |
| Prenatal care (vs no) | 0.46 (0.46-0.47) | 0.73 (0.70-0.76) |
| Prepregnancy diabetes (vs no) | 2.07 (2.04-2.10) | 1.53 (1.43-1.64) |
| Gestational diabetes (vs no) | 1.20 (1.19-1.21) | 0.92 (0.88-0.96) |
| Prepregnancy hypertension (vs no) | 2.05 (2.02-2.07) | 1.00 (0.95-1.06) |
| Gestational hypertension (vs no) | 2.30 (2.29-2.32) | 0.77 (0.75-0.80) |
| Hypertension eclampsia (vs no) | 3.34 (3.25-3.43) | 0.75 (0.65-0.85) |
| WIC benefits (vs no) | 0.87 (0.86-0.87) | 0.84 (0.83-0.86) |
| Gravida (vs 1) | ||
| 2 | 1.06 (1.05-1.07) | 1.12 (1.07-1.17) |
| 3 | 1.09 (1.08-1.11) | 1.13 (1.06-1.20) |
| 4 | 1.13 (1.11-1.16) | 1.08 (0.99-1.17) |
| Para (vs 1) | ||
| 2 | 0.99 (0.98-1.00) | 0.93 (0.89-0.97) |
| 3 | 1.05 (1.04-1.07) | 0.99 (0.93-1.05) |
| 4 | 1.17 (1.15-1.19) | 1.06 (0.99-1.14) |
| Aborta (vs 0) | ||
| 1 | 1.00 (0.99-1.01) | 1.02 (0.99-1.05) |
| 2 | 1.05 (1.04-1.07) | 1.08 (1.03-1.13) |
| 3 | 1.11 (1.09-1.13) | 1.12 (1.05-1.20) |
| 4 | 1.17 (1.15-1.19) | 1.16 (1.08-1.25) |
| Plurality (vs 1) | ||
| 2 | 8.97 (8.91-9.04) | 1.14 (1.10-1.18) |
| ≥3 | 16.56 (15.83-17.32) | 1.24 (1.10-1.39) |
| Cigarette smoking 3 mo before pregnancy (vs no) | 0.93 (0.92-0.95) | 1.08 (1.03-1.13) |
| Cigarette smoking during pregnancy (vs no) | 1.33 (1.31-1.34) | 1.20 (1.14-1.27) |
| Method of delivery (vs spontaneous) | ||
| Forceps | NA | 1.00 (0.87-1.15) |
| Vacuum | NA | 0.76 (0.70-0.82) |
| Cesarean | NA | 0.92 (0.91-0.94) |
| Gestational age category (vs normal term) | ||
| Moderate-to-late preterm | NA | 2.74 (2.67-2.82) |
| Very preterm | NA | 10.57 (10.21-10.95) |
| Extremely preterm | NA | 128.71 (125.87-131.63) |
Abbreviations: NA, not applicable; OR, odds ratio; WIC, Special Supplemental Nutrition Program for Women, Infants, and Children.
a
In all, 1 142 904 observations (10.3%) were deleted from the regression because of a missing value on 1 or more covariates.