The frequency and clinical significance of intra-amniotic inflammation in patients with a positive cervical fetal fibronectin.
OBJECTIVE
A positive fetal fibronectin result in cervicovaginal fluid is a powerful predictor of preterm delivery and is considered a marker for upper genital tract infection (ie, intrauterine infection). Treatment with antimicrobial agents is being considered in patients with a positive fetal fibronectin test of cervico/vaginal fluid. This study was undertaken to determine the frequency and clinical significance of intra-amniotic infection/inflammation in patients with a positive fetal fibronectin.


METHODS
A total of 1709 pregnant women (gestational age, 23-31 weeks) were screened for cervical fetal fibronectin. Patients with a positive fibronectin were offered amniocentesis for the diagnosis of intra-amniotic infection and treatment with antibiotics. Amniocentesis was performed in 58 patients with a positive fibronectin test (>50 ng/mL). Amniotic fluid was cultured for aerobic/anaerobic bacteria and mycoplasmas. Polymerase chain reaction assay for Ureaplasma urealyticum was performed. Interleukin-6 concentrations were measured by a specific immunoassay. Nonparametric statistics were used for analysis.


RESULTS
None of the patients with a positive fibronectin had a positive amniotic fluid culture. U urealyticum was detected in 1 case (1.8%) with the polymerase chain reaction assay. Amniotic fluid IL-6 was elevated (>2.5 ng/mL) in 5.3% of patients (3/57 patients); all of these patients delivered preterm neonates. There was no relationship between amniotic fluid IL-6 and cervical fibronectin concentration (r = 0.14;P: >.1). Patients who delivered preterm (<34 weeks) had higher median amniotic fluid IL-6 and cervical fetal fibronectin concentrations than those patients who delivered after 34 weeks (IL-6: median, 2.1 ng/mL [range, 0.1-25.3 ng/mL] vs median, 0.3 ng/mL [0.03-2.4 ng/mL]; P <.05; fibronectin: median, 509 ng/mL [260->1000 ng/mL] vs median, 155 ng/mL [50-889 ng/mL]; P <.01).


CONCLUSIONS
Intra-amniotic infection was detected in 1.8% of cases with a positive fibronectin in the cervical fluid; intra-amniotic inflammation was present in 5.3% of cases. All patients with a positive fetal fibronectin and intra-amniotic inflammation delivered preterm neonates.
Yoon
B H
BH
Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Korea.
Romero
R
R
Moon
J B
JB
Oh
S Y
SY
Han
S Y
SY
Kim
J C
JC
Shim
S S
SS
D000328:Adult; D000653:Amniotic Fluid / Q000737:chemistry / Q000382:microbiology; D002584:Cervix Uteri / Q000378:metabolism*; D002821:Chorioamnionitis / Q000453:epidemiology* / Q000503:physiopathology*; D005260:Female; D005353:Fibronectins; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D015850:Interleukin-6 / Q000032:analysis; D009994:Osmolar Concentration; D011247:Pregnancy; D016990:Ureaplasma urealyticum / Q000302:isolation & purification
C403421:FFN protein, human; D005353:Fibronectins; D006023:Glycoproteins; D015850:Interleukin-6