Table 2.
Risk factors for intrapartum stillbirth relative to antepartum stillbirth, 24–43 weeks of gestation, United States 2014
| Intrapartum death | ||
|---|---|---|
| Unadjusted RR (95% CI) |
Adjusted a RR (95% CI) |
|
| Male sex | 0.99 (0.83, 1.18) | 0.99 (0.83, 1.18) |
| Age at delivery (years) | ||
| < 20 | 1.16 (0.82, 1.64) | 1.09 (0.77, 1.54) |
| 20–24 | 1.00 (Reference) | 1.00 (Reference) |
| 25–34 | 0.89 (0.72, 1.11) | 0.99 (0.78, 1.25) |
| ≥ 35 | 0.90 (0.68, 1.18) | 1.06 (0.78, 1.43) |
| Maternal education < Bachelor’s degree b | 1.20 (0.95, 1.53) | 1.26 (0.96, 1.66) |
| Primipara c | 1.33 (1.11, 1.59) | 1.32 (1.08, 1.61) |
| Timing of first prenatal care visit | ||
| First trimester | 1.00 (Reference) | 1.00 (Reference) |
| After first trimester | 1.08 (0.86, 1.35) | 1.06 (0.85, 1.33) |
| No care | 1.08 (0.73, 1.60) | 1.04 (0.69, 1.54) |
| Maternal cigarette smoking d | 1.06 (0.81, 1.41) | 1.02 (0.76, 1.36) |
| Pre-pregnancy body mass index (kg/m2) e | ||
| Underweight | 1.46 (0.90, 2.35) | 1.43 (0.88, 2.31) |
| Normal | 1.00 (Reference) | 1.00 (Reference) |
| Overweight | 1.01 (0.80, 1.29) | 1.04 (0.81, 1.32) |
| Obese class I | 0.99 (0.76, 1.32) | 1.05 (0.79, 1.39) |
| Obese class II | 0.92 (0.63, 1.32) | 0.95 (0.65, 1.38) |
| Obese class III | 0.92 (0.62, 1.36) | 0.95 (0.63, 1.44) |
| Maternal race f | ||
| White | 1.00 (Reference) | 1.00 (Reference) |
| Black | 0.75 (0.60, 0.95) | 0.70 (0.55, 0.89) |
| American Indian/Alaska Native | 1.51 (0.83, 2.75) | 1.43 (0.78, 2.60) |
| Asian/Pacific Islander | 0.84 (0.54, 1.29) | 0.85 (0.55, 1.31) |
| Hispanic | 0.96 (0.76, 1.21) | 0.95 (0.74, 1.21) |
| Pre-pregnancy diabetes g | 0.96 (0.63, 1.47) | 0.96 (0.62, 1.48) |
| Gestational diabetes h | 0.71 (0.46, 1.09) | 0.71 (0.46, 1.09) |
| Pre-pregnancy hypertension i | 0.85 (0.56, 1.30) | 0.96 (0.62,1.50) |
| Gestational hypertension j | 1.45 (1.09, 1.93) | 1.47 (1.09, 1.96) |
| Eclampsia k | 1.34 (0.58, 3.12) | 1.25 (0.54, 2.91) |
| In-hospital delivery l | 0.63 (0.35, 1.14) | 0.64 (0.35,1.17) |
| Attendant | ||
| Doctor of Medicine | 1.00 (Reference) | 1.00 (Reference) |
| Doctor of Osteopathy | 0.82 (0.57, 1.19) | 0.79 (0.54, 1.15) |
| Certified Nurse Midwife/Other | 0.87 (0.54, 1.40) | 0.78 (0.48, 1.26) |
RR risk ratio
aAdjusted for all other risk factors in the table. Antepartum stillbirths are the comparison group. bReference group is ≥ Bachelor’s degree. cParity includes prior live births, now living or dead; reference group is multipara. dMaternal cigarette use at any time during pregnancy. Reference category is no smoking. eUnderweight (< 18.5), Normal (18.5–24.9), Overweight (25–29.9), Obese class I (30–34.9), Obese class II (35–39.9), Obese class III (≥40). fIndividuals for whom Hispanic ethnicity was unknown were assumed to be non-Hispanic. g-kReference group includes those without a reported diagnosis of the condition lReference group is out of hospital place of delivery