Table 1.

Clinical characteristics and pregnancy outcomes of the study population according to the results of AF culture and MMP-8 concentrations

	(−) AF culture Low MMP-8 (group 1; n=81)	P*	(−) AF culture High MMP-8 (group 2; n=31)	P†	(+) AF culture (group 3; n=28)	P‡
Maternal age (y)	30 (21–45)	NS	31 (23–39)	NS	29 (24–37)	NS
Nulliparity (n)	40 (49%)	NS	9 (29%)	NS	9 (32%)	NS
GA at amniocentesis (week)#	33.3 (20.4–35.0)	<.001	29.7 (21.3–34.7)	NS	29.6 (21.6–34.3)	<.001
GA at delivery (week)#	34.7 (23.7–41.6)	<.001	30.9 (22.3–35.7)	NS	30.0 (21.9–34.7)	<.001
Amniocentesis-to-delivery interval (hour)§	141 (0–3545)	<.005	46 (0–1849)	NS	116 (2–748)	<.005
AF WBC (cells/mm3)#	1 (0–250)	<.001	153 (0- >1000)	NS	270 (0- >1000)	<.001
AF MMP-8 (ng/mL)#	1.1 (0.3–22.3)	<.001	211.8 (35.0–2874.5)	NS	119.3 (1.6–5019.5)	<.001

Values are medians and ranges.

AF, amniotic fluid; MMP-8, matrix metalloproteinase-8; Low MMP-8, matrix metalloproteinase-8 <23 ng/mL; High MMP-8, matrix metalloproteinase-8 >23 ng/mL; GA, gestational age; NS, not significant; WBC, white blood cell

^*Comparison between groups 1 and 2.

^†Comparison between groups 2 and 3.

^‡Comparison between groups 3 and 1.

^#P<.05, by Kruskal-Wallis ANOVA test

^§Compared by generalized Wilcoxon test for survival analysis.