The relationship between the intensity of intra-amniotic inflammation and the presence and severity of acute histologic chorioamnionitis in preterm gestation

Figures & data

Table 1. Clinical characteristics of patients according to the presence or absence of acute histologic chorioamnionitis.

	Acute histologic chorioamnionitis		p value
Characteristics	Present (n = 183)	Absent (n = 229)	Unadjusted	Adjusted¶
Maternal age (years)*	30.0 (21–43)	30.0 (21–41)	0.74	–
Nulliparity (n)	86 (47.0%)	109 (47.6%)	0.92	–
Gestational age at amniocentesis (week)*	30.9 (23.7–34.9)	32.7 (24.0–34.9)	<0.001	–
Gestational age at delivery (week)*	31.3 (24.0–35.0)	32.9 (24.0–35.0)	<0.001	0.002
Birth weight (g)*	1580 (500–3950)	1710 (450–3280)	0.025	<0.001
Amniocentesis to delivery interval (h)*	18.0 (0.0–118.3)	4.2 (0.0–106.7)	<0.001	0.001
Positive AF culture (n/N)†	56/180 (31.1%)	18/220 (8.2%)	<0.001	<0.001
AF MMP-8 concentration (ng/ml)*	188.3 (0.3–6142.6)	1.8 (0.3–2845.5)	<0.001	<0.001
IAI (n)‡	133 (72.7%)	40 (17.5%)	<0.001	<0.001

AF, amniotic fluid; MMP-8, matrix metalloproteinase-8; IAI, intra-amniotic inflammation.

*Median value and range.

†Total cases with AF culture results: 400.

‡AF MMP-8 concentration >23 ng/ml.

¶Adjusted for gestational age at amniocentesis.

Table 2. The prevalence of funisitis, amnionitis and positive amniotic fluid culture according to the total grade of acute histologic chorioamnionitis.

Total grade of HCA	Prevalence of each grade (%)	Funisitis (n)	p*	Amnionitis (n)	p*	AF culture (n)	p*
0 (n = 229)	55.6	4 (1.7%)	<0.001	0	<0.001	18 (8.2%)	<0.001
1 (n = 78)	18.9	15 (19.2%)		0		19 (24.7%)
2 (n = 38)	9.2	21 (55.3%)		21 (55.3%)		16 (43.2%)
3 (n = 32)	7.8	20 (62.5%)		27 (84.4%)		8 (25.0%)
4 (n = 19)	4.6	17 (89.5%)		18 (94.7%)		6 (31.6%)
5 (n = 5)	1.2	4 (80.0%)		5 (100.0%)		3 (60.0%)
6 (n = 11)	2.7	10 (90.9%)		11 (100.0%)		4 (40.0%)

HCA, acute histologic chorioamnionitis; AF, amniotic fluid.

*Linear-by-linear association.

Table 3. The prevalence of intra-amniotic inflammation and amniotic fluid matrix metalloproteinase-8 concentration, amniotic fluid white blood cell count according to the total grade of acute histologic chorioamnionitis.

Total grade of HCA	IAI‡ (n)	p*	AF MMP-8 (ng/ml)¶	p†	AF WBC¶	p†
0 (n = 229)	17.5% (40)	<0.001	1.8 (0.3–2845.5)	<0.001	2 (0–7200)	<0.001
1 (n = 78)	51.3% (40)		25.9 (0.3–4202.7)		5 (0–50 000)
2 (n = 38)	81.6% (31)		229.7 (0.3–3929.0)		405 (0–13 248)
3 (n = 32)	96.9% (31)		486.2 (0.4–3392.0)		478 (0–15 000)
4 (n = 19)	89.5% (17)		422.4 (0.6–6142.6)		892 (1–5800)
5 (n = 5)	100.0% (5)		257.0 (35.1–1007.3)		198 (17–>1000)
6 (n = 11)	81.8% (9)		1475.7 (0.5–3116.7)		1026 (1–8640)

HCA, acute histologic chorioamnionitis; IAI, intra-amniotic inflammation; AF, amniotic fluid; MMP-8, matrix metalloproteinase-8; WBC, white blood cell.

*Linear-by-linear association.

†Kruskal–Wallis analysis test and Jonckheere–Terpstra test.

‡AF MMP-8 concentration >23 ng/ml.

¶Values are given as median (range).

Figure 1. Amniotic fluid MMP-8 concentration was positively correlated with the total grade of HCA (r²= 0.37, p < 0.001 by Spearman’s rho).