The frequency and risk factors of funisitis and histologic chorioamnionitis in pregnant women at term who delivered after the spontaneous onset of labor

Figures & data

Table I. Clinical characteristics and pregnancy outcomes according to the presence or absence of funisitis.

	Funisitis		p Value
	Absent (n = 1228)	Present (n = 88)
Clinical characteristics
Age (years)*	31.1 ± 3.4	31.1 ± 3.6	NS
Nulliparity	679 (55.3%)	63 (71.6%)	<0.005
Maternal age ≥ 35 years old	179 (14.6%)	13 (14.8%)	NS
Hypertensive disease in pregnancy	21 (1.7%)	1 (1.1%)	NS
Diabetes	15 (1.2%)	0 (0%)	NS
Duration of ROM (hours)*	5.3 ± 10.1	7.8 ± 14.2	<0.05
Total duration of labor (hours)*,^†	3.4 ± 2.9	5.9 ± 3.6	<0.001
Duration of 1st stage of labor (hours)*,^†	2.5 ± 2.4	4.6 ± 3.1	<0.001
Duration of 2nd stage of labor (hours)*,^†	0.9 ± 0.9	1.3 ± 1.3	<0.005
Use of oxytocin augmentation	384 (31.3%)	35 (39.8%)	NS
Use of epidural analgesia	423 (34.4%)	45 (51.1%)	<0.005
Pregnancy outcomes
Gestational age (weeks)*	39.7 ± 1.0	39.9 ± 1.0	<0.05
Birth weight(g)*	3266 ± 384	3396 ± 405	<0.01
Birth weight > 4000 g	39 (3.2%)	8 (9.1%)	<0.05
Small-for-gestational age neonates	81 (6.6%)	4 (4.5%)	NS
Large-for-gestational age neonates	137 (11.2%)	15 (17.0%)	NS
Cesarean delivery	52 (4.2%)	8 (9.1%)	0.056
Cesarean delivery due to failure to progress	40 (3.3%)	6 (6.8%)	NS
Cesarean delivery due to fetal distress	11 (0.9%)	2 (2.3%)	NS
Operative vaginal delivery	148 (12.1%)	18 (20.5%)	<0.05
1-Min Apgar score < 7	28 (2.3%)	3 (3.4%)	NS
5-Min Apgar score < 7	10 (0.8%)	0 (0%)	NS
Positive meconium staining at birth	243 (19.8%)	43 (48.9%)	<0.001
pH of umbilical artery at birth*	7.282 ± 0.060	7.267 ± 0.061	<0.01
Base excess of umbilical artery at birth (mmol/l)*	(−4.148) ± 2.694	(−5.052) ± 2.882	<0.005
pO2 of umbilical artery at birth (mmHg)*	20.224 ± 9.324	18.793 ± 6.443	<0.05
Saturation of O2 in umbilical artery at birth (%)*	31.634 ± 15.472	28.885 ± 15.856	<0.05
NICU admission	21 (1.7%)	4 (4.5%)	0.08

ROM, rupture of membranes; NS, not significant.

*Values are given as mean ± standard deviation.

^†Duration of labor was analyzed only in cases who admitted before cervical dilatation of 4 cm; duration of 1st stage was defined as duration of cervical dilatation from 4 to 10 cm; duration of 2nd stage was defined as duration between full cervical dilatation and fetal delivery.

Table II. Clinical characteristics and pregnancy outcomes according to the presence or absence of histologic chorioamnionitis.

	Histologic chorioamnionitis		p Value
	Absent (n = 1006)	Present (n = 310)
Clinical characteristics
Age (years)*	31.1 ± 3.5	31.0 ± 3.4	NS
Nulliparity	524 (52.1%)	218 (70.3%)	<0.001
Maternal age ≥ 35 years old	149 (14.8%)	43 (13.9%)	NS
Hypertensive disease in pregnancy	18 (1.8%)	4 (1.3%)	NS
Diabetes	14 (1.4%)	1 (0.3%)	NS
Duration of ROM (hours)*	4.8 ± 8.4	7.6 ± 15.1	<0.001
Total duration of labor (hours)*,^†	3.1 ± 2.7	4.9 ± 3.4	<0.001
Duration of 1st stage of labor (hours)*,^†	2.3 ± 2.3	3.6 ± 2.9	<0.001
Duration of 2nd stage of labor (hours)*,^†	0.8 ± 0.8	1.3 ± 1.2	<0.001
Use of oxytocin augmentation	288 (28.6%)	131 (42.3%)	<0.001
Use of epidural analgesia	313 (31.1%)	155 (50.0%)	<0.001
Pregnancy outcomes
Gestational age (weeks)*	39.6 ± 1.0	39.8 ± 0.9	<0.005
Birth weight(g)*	3258 ± 383	3331 ± 393	<0.05
Birth weight > 4000 g	27 (2.7%)	20 (6.5%)	<0.005
Small-for-gestational age neonates	70 (7.0%)	15 (4.8%)	NS
Large-for-gestational age neonates	106 (10.5%)	46 (14.8%)	<0.05
Cesarean delivery	35 (3.5%)	25 (8.1%)	<0.005
Cesarean delivery due to failure to progress	24 (2.4%)	22 (7.1%)	<0.001
Cesarean delivery due to fetal distress	10 (1.0%)	3 (1.0%)	NS
Operative vaginal delivery	111 (11.0%)	55 (17.7%)	<0.005
1-Min Apgar score < 7	26 (2.6%)	5 (1.6%)	NS
5-Min Apgar score < 7	10 (1.0%)	0 (0%)	NS
Positive meconium staining at birth	193 (19.2%)	93 (30.0%)	<0.001
pH of umbilical artery at birth*	7.283 ± 0.061	7.277 ± 0.060	<0.05
Base excess of umbilical artery at birth (mmol/l)*	(−4.14) ± 2.72	(−4.44) ± 2.70	<0.05
pO2 of umbilical artery at birth (mmHg)*	20.282 ± 9.187	19.625 ± 9.078	<0.05
Saturation of O2 in umbilical artery at birth (%)*	31.926 ± 15.604	29.922 ± 15.119	<0.05
NICU admission	19 (1.9%)	6 (1.9%)	NS

ROM, rupture of membranes; NS, not significant.

*Values are given as mean ± standard deviation.

^†Duration of labor was analyzed only in cases who admitted before cervical dilatation of 4 cm; duration of 1st stage was defined as duration of cervical dilatation from 4 to 10 cm; duration of 2nd stage was defined as duration between full cervical dilatation and fetal delivery.

Table III. Relationship of various independent antepartum risk factors with funisitis and histologic chorioamnionitis, analyzed by overall logistic regression analysis.

Variables	Odds ratio	95% Confidence interval	Significance
Funisitis
Nulliparity	1.354	0.697–2.629	NS
Total duration of labor	1.208	1.110–1.316	<0.001
Duration of ROM	1.006	0.987–1.025	NS
Use of oxytocin augmentation	0.683	0.382–1.221	NS
Use of epidural analgesia	0.964	0.516–1.800	NS
Gestational age	1.193	0.902–1.578	NS
Large-for-gestational age neonates	1.299	0.649–2.599	NS
Cesarean delivery	0.755	0.259–2.198	NS
Operative vaginal delivery	1.432	0.760–2.701	NS
Histologic chorioamnionitis
Nulliparity	1.549	1.070–2.243	<0.05
Total duration of labor	1.133	1.069–1.201	<0.001
Duration of ROM	1.003	0.990–1.016	NS
Use of oxytocin augmentation	0.996	0.711–1.396	NS
Use of epidural analgesia	1.135	0.788–1.634	NS
Gestational age	1.124	0.959–1.318	NS
Large-for-gestational age neonates	1.391	0.886–2.183	NS
Cesarean delivery	1.327	0.682–2.580	NS
Operative vaginal delivery	1.144	0.753–1.741	NS

NS, not significant; ROM, rupture of membranes.

Figure 1.  The frequency of funisitis and histologic chorioamnionitis as a function of total duration of labor. The frequency of funisitis (□) and histologic chorioamnionitis (▪) increased according to the total duration of labor (p < 0.001 for each; χ² test for trend).