Table 1.

Clinical characteristics of the study population according to the presence or absence of microbial invasion of the amniotic cavity and/or intra-amniotic inflammation

	MIAC and/or IAI (n=40)	MIAC (−)/IAI (−) (n=12)	P
Maternal age, years	31.5 (28.5–36)	29.5 (27–31)	.112
Nulliparity	40 (16/40)	66.7 (8/12)	.186
Gestational age at amniocentesis, weeks	25.8 (23.7–30.0)	31.4 (28.3–33.3)	.006
Diagnosis
Preterm PROM	32.5 (13/40)	8.3 (1/12)	.144
Preterm labor	47.5 (19/40)	75.0 (9/12)	.133
Acute cervical insufficiency	10.0 (4/40)	0 (0/12)	.562
Clinical chorioamnionitis alone	10.0 (4/40)	16.7 (2/12)	.612
Maternal body temperature, °C	38.2 (38.0–38.3)	38.3 (38.0–38.6)	.758
Maternal blood WBC count, × 103 cells/mm3	15.2 (12.3–17.7)	16.3 (8.5–18.0)	.862
Antibiotic use	95.0 (38/40)	69.2 (8/12)	.021
Before amniocentesis	55.0 (22/40)	25.0 (3/12)	.101
Corticosteroid use	42.5 (17/40)	41.7 (5/12)	1.000
Before amniocentesis	32.5 (13/40)	25.0 (3/12)	.733

Data are presented as median (interquartile range) or % (n/N).

IAI: intra-amniotic inflammation, defined as an amniotic fluid matrix metalloproteinase-8 concentration >23 ng/mL.

MIAC: microbial invasion of amniotic cavity, defined as a positive amniotic fluid culture.

PROM: preterm rupture of the membranes.

WBC: white blood cell.