Changes in amniotic fluid concentration of thrombin–antithrombin III complexes in patients with preterm labor: Evidence of an increased thrombin generation

Figures & data

Table I.  Demographic and clinical characteristics of the study population.

	Term not in labor (n = 39)	Term in labor (n = 25)	Term labor with IAI (n = 22)	p
Maternal age (years)	24 (21–30)	23 (20–27)	25 (21.8–29.3)	0.6
Gravidity	2 (2–4)	1.5 (1–2)	2 (1–3)	0.06
Gestational age at amniocentesis (weeks)	39 (39–40)	40 (39–40)	39 (38–40)	0.2
Gestational age at delivery (weeks)	39 (39–40)	40 (39–40)	39 (38–40)	0.2
Neonatal birthweight (g)	3260 (3085–3475)	3580 (3172.5–3760)	3320 (3100–3730)	0.2

Data is presented as median (iterquertile range).

PTL, preterm labor; IAI, intra-amniotic infection/inflammation.

Table II. Demographic and clinical characteristics of the preterm study population.

ss	PTL delivered at term (n = 62)	PTL without IAI (n = 59)	PTL with IAI (n = 71)	p
Maternal age (years)	21.5 (19–25.7)	22 (19–28.2)	23 (19.5–27.5)	0.7
Gravidity	3 (2–4)	3 (2–5)	3 (2–5)	0.7
Gestational age at amniocentesis (weeks)	31.9 (29.9–33.1)	29.4 (26.3–31.7)	27.0 (25.1–31.9)	<0.001
Gestational age at delivery (weeks)	38.6 (38–39.4)	31.2 (29.0–33.8)	28.5 (25.0–32.3)	<0.001
Neonatal birthweight (g)	3000 (2720–3400)	1639.5 (1100–2262)	1060 (695–1735)	<0.001

Data is presented as median (iterquertile range).

PTL, preterm labor; IAI, intra-amniotic infection/inflammation.

Figure 1.  Amniotic fluid thrombin-antithrombin III complexes concentration in patients in the mid-trimester of pregnancy and women at term not in labor (mid-trimester: median 8.1 μg/L, range 2.1–160.0 vs. term no labor: median 66.9 μg/L, range 10.2–154).

Figure 2.  Amniotic fluid thrombin-antithrombin III complexes concentration in patients with term pregnancies not in labor, women at term in labor and patients with term labor and intra-amniotic infection/inflammation (term no labor: median 66.9 μg/L, range 10.2–154; term in labor: median 50.8 mg/L, range 6.8–150.0); term labor with IAI: median 118.5 μg/L, range 26.3–310.0.

Figure 3.  Amniotic fluid thrombin-antithrombin III complexes concentration in patients with preterm labor who delivered at term, women with preterm labor who delivered preterm without intra-amniotic infection/inflammation, and women with preterm labor and intra-amniotic infection/inflammation (PTL with IAI: median 147.7 μg/L, range 15.3–1424.8; PTL without IAI: median 116.0 μg/L, range 10.7–2073.9; PTL who delivered at term: median 73.4 μg/L, range 7.6–507.0).

Figure 4.  (a) The effect of an elevated amniotic fluid thrombin–antithrombin III complexes concentration on gestational age at delivery in patients with preterm labor. (b) The effect of an elevated amniotic fluid thrombin–antithrombin III complexes concentration on the amniocentesis-to-delivery interval in patients with preterm labor.

Figure 5.  (a) The effect of an elevated amniotic fluid thrombin–antithrombin III complexes concentration on gestational age at delivery, among patients with preterm labor without intra-amniotic infection/inflammation. (b) The effect of an elevated amniotic fluid thrombin–antithrombin III complexes concentration on the amniocentesis-to-delivery interval of patients with preterm labor without intra-amniotic infection/inflammation.

Table III.  Cox proportional hazards survival analysis in the prediction of amniocentesis-to-delivery interval.

Covariates	Hazard ratio	95% Confidence interval	p
Elevated amniotic fluid thrombin–antithrombin III complexes concentration*	1.5	1.07–2.1	0.02
Gestational age at amniocentesis (wk)	0.98	0.93–1.03	0.45
Cervical dilatation at amniocentesis (cm)	1.3	1.2–1.4	<0.001

*Variable was dichotomized: amniotic fluid thrombin–antithrombin III complex concentration (<108.24 μg/l vs.≥108.24 μg/l).