Table 2.
Univariable and multivariable logistic regression analysis of variables potentially associated with sPTB in the subsequent pregnancy (n = 1643).
| Spontaneous PTB in the subsequent pregnancy | ||||||
|---|---|---|---|---|---|---|
| n/N (%) | cOR | 95%CI | aOR | 95%CI | ||
| Index pregnancy | Maternal age ≥ 35 years | 13/305 (4.3) | 1.5 | (0.8–2.8) | 1.4 | (0.7–2.7) |
| Maternal age < 20 years | 2/29 (6.9) | 2.3 | (0.5–10.0) | 1.6 | (0.3–9.2) | |
| Pre-pregnancy BMI < 18.5 kg/m2 | 16/321 (5.0) | 1.9* | (1.0–3.4) | 1.7 | (0.9–3.3) | |
| Nulliparity | 38/1313 (2.9) | 0.7 | (0.4–1.3) | 0.7 | (0.4–1.4) | |
| Spontaneous PTB | 16/66 (24.2) | 13.7* | (7.1–26.3) | 12.7* | (6.5–24.8) | |
| Inter-pregnancy | Pregnancy interval, years | – | 1.1 | (0.9–1.5) | 1.1 | (0.8–1.5) |
| Anuual BMI change, kg/m2/year | – | 0.7* | (0.5–0.9) | 0.6* | (0.5–0.9) | |
n/N: The number of sPTB events in the subsequent pregnancy/the number of patients for each variables; cOR, clude odds ratio; aOR, adjusted OR; CI, confidence interval; BMI, body mass index; PTB, preterm birth.
*Statistically significant.