Table 3.
Log binomial regression model to show the association between various socio-demographic and comorbid characteristics and preterm birth (1989–2017).
| Any preterm | Extreme preterm | Very preterm | Moderate-to-late preterm | |||||
|---|---|---|---|---|---|---|---|---|
| RR and 95% CI | p value | RR and 95% CI | p value | RR and 95% CI | p value | RR and 95% CI | p value | |
| Race | ||||||||
| White | Reference | |||||||
| Black | 1.66 (1.65–1.67) | <0.001 | 2.69 (2.64–2.75) | <0.001 | 2.02 (1.99–2.05) | <0.001 | 1.54 (1.53–1.55) | <0.001 |
| Plurality | ||||||||
| Singleton | Reference | |||||||
| Twin | 13.47 (13.31–13.63) | <0.001 | 26.49 (25.75–27.26) | <0.001 | 19.78 (19.33–20.24) | <0.001 | 11.86 (11.71–12.00) | <0.001 |
| Higher-order multiples | 168.25 (149.48–190.19) | <0.001 | 1073.20 (929.10–1242.96) | <0.001 | 668.88 (586.70–765.28) | <0.001 | 103.33 (91.21–117.57) | <0.001 |
| Age group | ||||||||
| Under 15 years | Reference | |||||||
| 15–24 years | 0.52 (0.49–0.54) | <0.001 | 0.40 (0.35–0.46) | <0.001 | 0.39 (0.35–0.43) | <0.001 | 0.54 (0.51–0.57) | <0.001 |
| 25–34 years | 0.40 (0.38–0.42) | <0.001 | 0.32 (0.28–0.36) | <0.001 | 0.27 (0.24–0.30) | <0.001 | 0.42 (0.40–0.45) | <0.001 |
| 35–44 years | 0.45 (0.42–0.47) | <0.001 | 0.35 (0.31–0.40) | <0.001 | 0.30 (0.27–0.34) | <0.001 | 0.47 (0.44–0.50) | <0.001 |
| 45–54 years | 0.57 (0.52–0.61) | <0.001 | 0.43 (0.33–0.54) | <0.001 | 0.40 (0.33–0.48) | <0.001 | 0.60 (0.55–0.65) | <0.001 |
| Parity | ||||||||
| 1–2 Children | Reference | |||||||
| 3–5 Children | 1.07 (1.06–1.07) | <0.001 | 0.84 (0.82–0.86) | <0.001 | 0.95 (0.94–0.97) | <0.001 | 1.09 (1.08–1.10) | <0.001 |
| 6 or more Children | 1.36 (1.35–1.38) | <0.001 | 1.17 (1.12–1.22) | <0.001 | 1.31 (1.27–1.36) | <0.001 | 1.37 (1.35–1.39) | <0.001 |
| Weight gain | ||||||||
| Up to 20 lb. | Reference | |||||||
| 21–30 lb. | 0.71 (0.70–0.71) | <0.001 | 0.26(0.25–0.26) | <0.001 | 0.54 (0.53–0.55) | <0.001 | 0.80 (0.80–0.81) | <0.001 |
| 31–40 lb. | 0.58 (0.57–0.58) | <0.001 | 0.14 (0.13–0.14) | <0.001 | 0.38 (0.37–0.39) | <0.001 | 0.69 (0.68–0.69) | <0.001 |
| Over 40 lb. | 0.49 (0.49–0.50) | <0.001 | 0.08 (0.07–0.08) | <0.001 | 0.27 (0.26–0.27) | <0.001 | 0.60 (0.59–0.60) | <0.001 |
| Diabetes | ||||||||
| No | Reference | |||||||
| Yes | 1.14 (1.13–1.16) | <0.001 | 0.48 (0.45–0.51) | <0.001 | 0.90 (0.87–0.94) | <0.001 | 1.23 (1.22–1.25) | <0.001 |
| Pregnancy hypertension | ||||||||
| No | Reference | |||||||
| Yes | 2.26 (2.23–2.29) | <0.001 | 1.64 (1.56–1.72) | <0.001 | 2.76 (2.68–2.85) | <0.001 | 2.19 (2.16–2.22) | <0.001 |
| Chronic hypertension | ||||||||
| No | Reference | |||||||
| Yes | 2.27 (2.24–2.30) | <0.001 | 1.82 (1.73–1.91) | <0.001 | 2.62 (2.53–2.71) | <0.001 | 2.24 (2.20–2.27) | <0.001 |
| Eclampsia | ||||||||
| No | Reference | |||||||
| Yes | 3.96 (3.83–4.09) | <0.001 | 4.36 (3.96–4.80) | <0.001 | 5.67 (5.31–6.04) | <0.001 | 3.28 (3.16–3.40) | <0.001 |