Table 4.

Magnitude of association between type of intra-amniotic inflammation and risk of spontaneous preterm delivery at <34 weeks of gestation both unrestricted and restricted to patients whose diagnosis of a sonographic short cervix was performed <24 weeks of gestation.

Study Group	n	%	Unadjusted			Adjusted*
			HR	95%CI		HR	95%CI
All the study population
No MIAC or intra-amniotic inflammation	174	75	1	reference		1	reference
MIAC	24	11	1.0	0.3	3.5	1.0	0.3	3.1
Microbial-associated intra-amniotic inflammation^	5	2	4.8	0.7	31.2	3.9	0.6	26.0
Sterile intra-amniotic inflammation	28	12	3.9	1.9	7.8	3.6	1.6	8.0
Sonographic short cervix <24 weeks
No MIAC or intra-amniotic inflammation	77	71	1	reference		1	reference
MIAC	15	14	1.6	0.4	5.9	1.6	0.5	5.0
Microbial-associated intra-amniotic inflammation^	3	3	13.6	4.7	39.3	14.7	2.8	75.8
Sterile intra-amniotic inflammation	13	12	4.3	1.8	10.5	5.4	1.5	19.0

Note: multivariable adjustments were made for maternal age, nulliparity, race, 17 OHPC treatment, smoking status and pre-pregnancy body mass index.

^{^}Interpretation of these hazard ratios should take into account the small number of subjects.

HR, hazard ratio,