On predicting time to completion for the first stage of spontaneous labor at term in multiparous women

Table 3 Multiple Regression Model Results Predicting Time to Completion of Cervical Dilation (Data from 1753 Partograms)

Variable	Coefficient^a	95% CI	p-value
Intercept	0.449	0.320–0.629	<0.001
Body mass index [kg/m²]	0.990	0.983–0.998	0.010
Parity 2 vs. 1	0.905	0.840–0.976	0.009
Parity ≥3 vs. 1	0.901	0.801–1.014	0.083
Spontaneous rupture of membranes [yes]	0.763	0.707–0.824	<0.001
Epidural [yes]	1.226	1.115–1.349	<0.001
Oxytocin [yes]	1.531	1.383–1.695	<0.001
Birthweight [kg]	1.393	1.293–1.502	<0.001
Cervical dilation^b			<0.001

^aValues are back-transformed from log scale, resulting in a model with multiplicative effects. A coefficient of 1 thus implies no effect
^bThe coefficients for cervical dilation were estimated with a smoothing GAMM function; see Figure 3

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