. Author manuscript; available in PMC: 2015 Jan 1.

Published in final edited form as: Ultrasound Obstet Gynecol. 2014 Jan;43(1):48–53. doi: 10.1002/uog.13206

Table 4.

Results from the Cox proportional hazards regression analyses predicting gestational age at birth from significant factors from multivariate regression analysis. (χ² = 118; p<0.0001)

	Hazard ratio	95% Confidence interval	p-value
Maternal age (years)	0.98	0.97 –1	0.1
History of prematurity	1.7	1.11– 2.91	0.015
Cervical length	0.98	0.98–0.997	0.004
Stage 2 TTTS	0.88	0.73 – 1.07	0.21
Cannula 12 Fr	1.33	1.01 – 1.74	0.04
Amnioinfusion	1.5	1.2 – 1.9	<0.0001
Collagen plug	0.69	0.5 – 0.94	0.02
iPPROM	2.42	1.93 – 3.03	<0.0001