Table 3.

Adjusted Odds Ratios and 95% Confidence Intervals for the Association Between Patient Factors and Preterm Birth at Less Than 37 Weeks of Gestation

Factor	Odds Ratio	95% Confidence Interval	P
Treatment group	0.99	0.68–1.46	.96
Maternal age (y)*	1.01	0.96–1.05	.76
Black race	1.07	0.72–1.58	.73
Public insurance	1.60	0.92–2.77	.10
Estimated gestational age at cervical length measurement (wk)*	1.02	0.89–1.16	.78
Cervical length (mm)*	0.93	0.90–0.97	<.001
Cervical funneling	1.20	0.72–2.00	.50
Intra-amniotic debris	0.96	0.53–1.73	.89
Any activity restriction	2.37	1.60–3.53	<.001

^*Odds ratio per 1 unit change.