Variable | β-Coefficient | Standard Error |
p Value
| |
---|---|---|---|---|

(Intercept) | 0.82 | 0.10 | < 0.001 | |

a | Parity (Multiparous) | 1.79 | 0.22 | < 0.001 |

b | Weight, pre-pregnancy (kg) | 61.21 | 11.84 | < 0.001 |

(Weight, pre-pregnancy)^{2}
| −12.45 | 7.35 | 0.09 | |

(Weight, pre-pregnancy)^{3}
| −6.48 | 5.07 | 0.20 | |

c |
BMI, pre-pregnancy (kg/m^{2})
| −57.98 | 8.56 | < 0.001 |

(BMI, pre-pregnancy)^{2}
| 9.42 | 5.90 | 0.11 | |

(BMI, pre-pregnancy)^{3}
| 12.68 | 5.04 | 0.01 | |

d | Gestational Age (weeks) | −6.01 | 2.66 | 0.02 |

(Gestational Age)^{2}
| −3.41 | 2.49 | 0.17 | |

(Gestational Age)^{3}
| 4.52 | 2.47 | 0.07 | |

e | Weight, at-delivery (kg) | −13.97 | 7.62 | 0.07 |

(Weight, at-delivery)^{2}
| 7.79 | 4.90 | 0.11 | |

f | Dilation (cm) | 23.57 | 3.98 | < 0.001 |

(Dilation)^{2}
| 4.97 | 3.87 | 0.20 | |

g | Maternal Age (years) | −8.43 | 2.57 | < 0.001 |

(Maternal Age)^{2}
| −4.35 | 2.34 | 0.06 | |

Equation |
Risk Score = 0.82 + [1.79 x a] + [61.21 x b] - [12.45 x b^{2}] - [6.48 x b^{3}] - [57.98 x c] + [9.42 x c^{2}] + [12.68 x c^{3}] - [6.01 x d] - [3.41 x d^{2}] + [4.52 x d^{3}] - [13.97 x e] + [7.79 x e^{2}] + [23.57 x f] + [4.97 x f^{2}] – [8.43 x g] – [4.35 x g^{2}]; probability of vaginal delivery = 1/(1 + e^{-Risk Score})
| |||

Model Performance |
Hosmer-Lemeshow goodness-of-fit χ2 = 5.02, 8 degrees of freedom, p = 0.76Area under receiver operating characteristic curve 0.81 [95% CI 0.78–0.83] |