Table II.

Demographic, clinical, laboratory and outcome characteristics of women with symptoms of preterm birth that provided AF samples for NGAL, MMP-9 and NGAL•MMP-9 complex levels (n=260).

Variable	Rule-out infection amniocenteses
	no IAI* & TB n = 39	no IAI* & PTB n = 132	yes IAI* & PTB n = 89	P value
Clinical and outcome characteristics at amniocentesis and at delivery
Maternal age, years, †	24 [19 – 31]	28 [23 – 32]	27 [23 – 34]	0.055
Parity †	0 [0 – 1]	0 [0 – 1]	1 [0 – 2]	0.450
Gravidity †	2 [1 – 3]	2 [1 – 4]	3 [2 – 3]	0.257
History of preterm birth ‡	4 (11)	36 (27)	24 (27)	0.090
GA at amniocentesis, weeks †	30 [26 – 32]	30 [27 – 32]	26 [24 – 29]	<0.001
GA at delivery, weeks †	39 [38 – 39]	31 [28 – 33]	26 [25 – 29]	<0.001
Amniocentesis-delivery interval, days †	61 [44 – 90]	4 [1 – 11]	0 [0 – 1]	<0.001
Amniocentesis-delivery < 7 days	1 (3%)	83 (63%)	83 (93%)	<0.001
Birthweight, grams †	3,150 [2,899 – 3,505]	1,708 [1,183 – 2,100]	930 [753 – 1,373]	<0.001
AF laboratory test results
Glucose, mg/dL †	32 [25 – 46]	28 [19 – 39]	4 [2 – 12]	<0.001
LDH activity, U/L †	156 [118 – 204]	176 [125 – 263]	744 [443 – 21,870]	<0.001
WBC count, cells/mm3 †	4 [1 – 10]	6 [2 – 21]	895 [180 – 1,967]	<0.001
Positive Gram stain ‡	0 (0%)	11 (8%)	53 (60%)	<0.001
Positive culture results ‡	0 (0%)	15 (11%)	65 (73%)	<0.001
Placental histology results	n=8	n=122	n=88
Chorionic plate inflammation, stage †	1 [0 – 2]	1 [0 – 2]	3 [3 – 3]	<0.001
Amnionitis, grade †	0 [0 – 0]	0 [0 – 1]	3 [2 – 3]	<0.001
Chorio-deciduitis, grade †	1 [0 – 3]	2 [0 – 3]	3 [3 – 4]	<0.001
Funisitis, grade †	0 [0 – 1]	0 [0 – 0]	2 [0 – 4]	<0.001

^*IAI was defined by an MR score 3 or 4 which is indicative of severe intra-amniotic inflammation.

^†Data presented as median [interquartile range] and analyzed by Kruskal-Wallis ANOVA on Ranks.

^‡Data presented as n (%) and analyzed by Chi square test.

Abbreviations: IAI, intra-amniotic inflammation; PTB, preterm birth <37weeks; TB, term birth ≥37weeks; GA, gestational age; LDH, lactate dehydrogenase