Amniotic fluid concentration of surfactant proteins in intra-amniotic infection

Figures & data

Table I.  Clinical and obstetrical characteristics of patients with and without intra-amniotic infection (IAI).

	Without IAI (N = 32)	With IAI (N = 16)	p-Value
Maternal age (years)	21 (16–39)	27 (16–36)	0.09
Nulliparity	16 (50%)	7 (43.8%)	0.7
Ethnicity
African-American	26 (81.3%)	15 (93.8%)	0.4
Caucasian	4 (12.5%)	1 (6.3%)
Hispanic	2 (6.3%)	0
GA at amniocentesis (weeks)	25.8 (18–33.3)	25.7 (18.4–33.3)	0.7
GA at delivery (weeks)	32 (19.1–41.4)	26.1 (18.5–33.3)	0.01*
Birth weight (grams)	1610 (100–3750)	625 (220–2300)	0.007*

GA, gestational age. Values are presented as median (range) or number (%). *p < 0.05.

Figure 1. Median amniotic fluid concentration of SP-B was significantly higher in patients with intra-amniotic infection (IAI) than those without IAI (IAI: median 40.2 ng/mL, range 0–809 ng/mL vs. without IAI: median 6.2 ng/mL, range 0–1035 ng/mL; p = 0.03). Similar result was observed after adjusting the amniotic fluid SP-B concentration according to the total protein concentration (SP-B/ total protein, IAI: median 7.19 ng/mg, range 0–237.5 ng/mg vs. without IAI: median 0.94 ng/mg, range 0–79.5 ng/mg; p = 0.03). *p < 0.05.

Table II.  Amniotic fluid concentrations of SP-A and SP-D in patients with and without intra-amniotic infection (IAI).

	Without IAI	With IAI	p-Value
SP-A (μg/mL)	1.73 (0.74–4.45) n = 32	1.56 (0.86–2.48) n = 14	0.5
SP-A/Pro (μg/mg)	0.29 (0.07–1.24) n = 32	0.21 (0.11–0.73) n = 14	0.3
SP-D (ng/mL)	7.15 (0–25.2) n = 20	8.05 (0–52.4) n = 10	0.7
SP-D/Pro (ng/mg)	0 (0–7.27) n = 20	0 (0–7.22) n = 10	0.9

Values are presented as median (range).

Table III.  Clinical and obstetrical characteristics of patients who had and who had not received antenatal corticosteroids within 7 days prior to amniocentesis, classified by the presence or absence of intra-amniotic infection (IAI).

	Steroids			No steroids
	Without IAI (n = 21)	With IAI (n = 9)	p-Value	Without IAI (n = 11)	With IAI (n = 7)	p-Value
Maternal age (years)	21 (19–39)	25 (16–32)	0.9	21 (16–26)	30 (18–36)	0.01*
GA at amniocentesis (weeks)	30.0 (23.0–33.3)	28.2 (24.0–33.3)	0.9	22.0 (18.0–27.3)	22.0 (18.4–26.2)	0.9
GA at delivery (weeks)	35.0 (23.5–38.5)	29.5 (24.1–33.3)	0.1	26.0 (19.1–41.4)	22.6 (18.5–28.0)	0.07
Birth weight (grams)	2230 (100–3750)	1416 (500–2300)	0.1	840 (320–3630)	440 (220–1470)	0.02*

GA, gestational age. Values are presented as median (range). *p < 0.05.

Figure 2. Among patients who had received antenatal corticosteroids within 7 days prior to amniocentesis, the median amniotic fluid concentration of SP-B was significantly higher in patients with intra-amniotic infection (IAI) than those without IAI (IAI: median 148 ng/mL, range 37.3–809 ng/mL vs. without IAI: median 7.2 ng/mL, range 0–1035 ng/mL; p = 0.005). Similar result was observed after adjusting the amniotic fluid SP-B concentration according to the total protein concentration (SP-B/ total protein, IAI: median 14.1 ng/mg, range 4.3–237.5 ng/mg vs. without IAI: median 1.45 ng/mg, range 0–79.5 ng/mg; p = 0.003). *p < 0.05.

Figure 3. Among patients who had not received antenatal corticosteroids within 7 days prior to amniocentesis, there was no significant difference in the median amniotic fluid concentration of SP-B between patients with and without intra-amniotic infection (IAI) (IAI: median 4 ng/mL, range 0–31.4 ng/mL vs. without IAI: median 3.4 ng/mL, range 0–37 ng/mL; p = 0.8). Similar result was observed after adjusting the amniotic fluid SP-B concentration according to the total protein concentration (SP-B/total protein, IAI: median 0.55 ng/mg, range 0–6.9 ng/mg vs. without IAI: median 0.59 ng/mg, range 0–3.3 ng/mg; p = 0.9).

Table IV.  Amniotic fluid concentrations of SP-A and SP-D in patients who had and who had not received antenatal corticosteroids within 7 days prior to amniocentesis.

	Steroids			No steroids
	Without IAI	With IAI	p-Value	Without IAI	With IAI	p-Value
SP-A (μg/mL)	2.12 (0.74–4.45) n = 21	1.75 (1.08–2.48) n = 8	0.41	0.33 (0.82–4.34) n = 11	1.49 (0.86–1.76) n = 6	0.8
SP-A/Pro (μg/mg)	0.36 (0.08–1.24) n = 21	0.27 (0.11–0.73) n = 8	0.4	0.23 (0.07–0.84) n = 11	0.20 (0.14–0.34) n = 6	0.4
SP-D (ng/mL)	6.10 (0–25.2) n = 15	10.6 (6.50–23.0) n = 5	0.2	11.8 (0–24.4) n = 5	6.2 (0–52.4) n = 5	0.7
SP-D/Pro (ng/mg)	0 (0–7.27) n = 15	1.03 (0–4.58) n = 5	0.5	1.16 (0–4.01) n = 5	0 (0–7.22) n = 5	0.4

IAI, intra-amniotic infection. Values are presented as median (range).