Chan Wook Park

The clinical significance of a positive Amnisure test in women with preterm labor and intact membranes

Objective. The Amnisure ROM™ test is approved for the diagnosis of rupture of membranes (ROM). Yet, a fraction of patients with a positive test have intact membranes by sterile speculum examination. The objective of this study was to determine the clinical significance of this finding. Methods. The study population consisted of four groups of nulliparous women at term: (1) not in labor without clinical evidence of ROM (n = 125); (2) in labor without clinical ROM with a negative Amnisure test™ (n = 56); (3) in labor without clinical ROM with a positive Amnisure test™ (n = 25); and (4) in labor with clinical ROM (n = 30). The Amnisure test™ was performed in cases without clinical ROM (Groups 1, 2 and 3). Results. (1) The Amnisure test™ was positive more frequently in women in labor with intact membranes than in patients not in labor at term without ROM (30.9% (25/81 women) vs. 4.8% (6/125 women); p < 0.001); (2) patients in labor without clinical ROM with a positive Amnisure test™ had a significantly shorter admission-to-delivery interval than those in labor without clinical ROM with a negative Amnisure test™ (p < 0.05). Conclusion. (1) A positive Amnisure test™ is present in about one-third nulliparous women at term presenting in labor with intact membranes; (2) patients with a positive Amnisure test™ had a shorter admission-to-delivery interval than those with a negative test.

The frequency and clinical significance of intra-amniotic inflammation in women with preterm uterine contractility but without cervical change: Do the diagnostic criteria for preterm labor need to be changed?

Objective: The objective of this study was to determine the frequency and clinical significance of intra-amniotic inflammation in patients with preterm increased uterine contractility with intact membranes but without cervical change. Methods: Amniocentesis was performed in 132 patients with regular uterine contractions and intact membranes without cervical change. Amniotic fluid was cultured for bacteria and mycoplasmas and assayed for matrix metalloproteinase-8 (MMP-8). Intra-amniotic inflammation was defined as an elevated amniotic fluid MMP-8 concentration (>23 ng/mL). Results: (1) Intra-amniotic inflammation was present in 12.1% (16/132); (2) Culture-proven intra-amniotic infection was diagnosed in 3% (4/132) of patients without demonstrable cervical change on admission or during the period of observation; and (3) Patients with intra-amniotic inflammation had significantly higher rates of preterm delivery and adverse outcomes, and shorter amniocentesis-to-delivery intervals than those without intra-amniotic inflammation (P < 0.05 for each). Adverse outcomes included chorioamnionitis, funisitis, and neonatal death. Conclusion: Intra-amniotic inflammation was present in 12% of patients with regular uterine contractions without cervical change, while culture-proven intra-amniotic infection was present in 3%. The presence of intra-amniotic inflammation was a significant risk factor for adverse neonatal outcomes. These observations question whether cervical changes should be required for the diagnosis of preterm labor, because patients without modifications in cervical status on admission or during a period of observation are at risk for adverse pregnancy outcomes.

The frequency and clinical significance of intra-amniotic inflammation defined as an elevated amniotic fluid matrix metalloproteinase-8 in patients with preterm labor and low amniotic fluid white blood cell counts

Objective To determine the frequency and clinical significance of intra-amniotic inflammation (IAI) defined as an elevated amniotic fluid (AF) matrix metalloproteinase-8 (MMP-8) concentration in patients with preterm labor and intact membranes (PTL) and low AF white blood cell (WBC) counts. Methods Adverse pregnancy outcomes were compared according to the presence or absence of IAI in 220 singleton gestations who underwent amniocentesis due to PTL (gestational age<35.7 weeks) and had low AF WBC counts (<19 cells/mm3). Adverse pregnancy outcomes included preterm birth within 5 days of amniocentesis, acute histologic chorioamnionitis (acute-HCA) and positive AF culture. IAI was defined as an elevated AF MMP-8 concentration (≥23 ng/mL). Results IAI was present in 19% of study population. Adverse pregnancy outcomes were significantly more frequent in patients with IAI than in those without IAI (preterm birth within 5 days of amniocentesis, 88% vs. 41%; acute-HCA, 47% vs. 11%; positive AF culture, 10% vs. 2%; each for P<0.05). Patients with IAI had a significantly shorter median amniocentesis-to-delivery interval than those without IAI (7.8 hours [0.01-3,307.3 hours] vs. 310.3 hours [0.01-2,973.8 hours]; P<0.001 from survival analysis). Multiple logistic regression analysis demonstrated that only an IAI (odds ratio, 3.3; 95% confidence interval, 1.5-7.3; P<0.005) retained a statistical significance in the prediction of acute-HCA after other confounding variables were adjusted. Conclusion Approximately one-fifth of patients with PTL and low AF WBC counts have an evidence of IAI and are at risk for impending preterm delivery and acute-HCA when AF MMP-8 concentration is used.

Bacteria and endotoxin in meconium-stained amniotic fluid at term: could intra-amniotic infection cause meconium passage?

Abstract Background: Meconium-stained amniotic fluid (MSAF) is a common occurrence among women in spontaneous labor at term, and has been associated with adverse outcomes in both mother and neonate. MSAF is a risk factor for microbial invasion of the amniotic cavity (MIAC) and preterm birth among women with preterm labor and intact membranes. We now report the frequency of MIAC and the presence of bacterial endotoxin in the amniotic fluid of patients with MSAF at term. Materials and methods: We conducted a cross-sectional study including women in presumed preterm labor because of uncertain dates who underwent amniocentesis, and were later determined to be at term (n = 108). Patients were allocated into two groups: (1) MSAF (n = 66) and (2) clear amniotic fluid (n = 42). The presence of bacteria was determined by microbiologic techniques, and endotoxin was detected using the Limulus amebocyte lysate (LAL) gel clot assay. Statistical analyses were performed to test for normality and bivariate comparisons. Results: Bacteria were more frequently present in patients with MSAF compared to those with clear amniotic fluid [19.6% (13/66) versus 4.7% (2/42); p < 0.05]. The microorganisms were Gram-negative rods (n = 7), Ureaplasma urealyticum (n = 4), Gram-positive rods (n = 2) and Mycoplasma hominis (n = 1). The LAL gel clot assay was positive in 46.9% (31/66) of patients with MSAF, and in 4.7% (2/42) of those with clear amniotic fluid (p < 0.001). After heat treatment, the frequency of a positive LAL gel clot assay remained higher in the MSAF group [18.1% (12/66) versus 2.3% (1/42), p < 0.05]. Median amniotic fluid IL-6 concentration (ng/mL) was higher [1.3 (0.7–1.9) versus 0.6 (0.3–1.2), p = 0.04], and median amniotic fluid glucose concentration (mg/dL) was lower [6 (0–8.9) versus 9 (7.4–12.6), p < 0.001] in the MSAF group, than in those with clear amniotic fluid. Conclusion: MSAF at term was associated with an increased incidence of MIAC. The index of suspicion for an infection-related process in postpartum women and their neonates should be increased in the presence of MSAF.

A new anti-microbial combination prolongs the latency period, reduces acute histologic chorioamnionitis as well as funisitis, and improves neonatal outcomes in preterm PROM

Abstract Objective: Antibiotic administration is a standard practice in preterm premature rupture of membranes (PROM). Specific anti-microbial agents often include ampicillin and/or erythromycin. Anaerobes and genital mycoplasmas are frequently involved in preterm PROM, but are not adequately covered by antibiotics routinely used in clinical practice. Our objective was to compare outcomes of PROM treated with standard antibiotic administration versus a new combination more effective against these bacteria. Study design: A retrospective study compared perinatal outcomes in 314 patients with PROM <34 weeks receiving anti-microbial regimen 1 (ampicillin and/or cephalosporins; n = 195, 1993–2003) versus regimen 2 (ceftriaxone, clarithromycin and metronidazole; n = 119, 2003–2012). Intra-amniotic infection/inflammation was assessed by positive amniotic fluid culture and/or an elevated amniotic fluid MMP-8 concentration (>23 ng/mL). Results: (1) Patients treated with regimen 2 had a longer median antibiotic-to-delivery interval than those with regimen 1 [median (interquartile range) 23 d (10–51 d) versus 12 d (5–52 d), p < 0.01]; (2) patients who received regimen 2 had lower rates of acute histologic chorioamnionitis (50.5% versus 66.7%, p < 0.05) and funisitis (13.9% versus 42.9%, p < 0.001) than those who had received regimen 1; (3) the rates of intra-ventricular hemorrhage (IVH) and cerebral palsy (CP) were significantly lower in patients allocated to regimen 2 than regimen 1 (IVH: 2.1% versus 19.0%, p < 0.001 and CP: 0% versus 5.7%, p < 0.05); and (4) subgroup analysis showed that regimen 2 improved perinatal outcomes in pregnancies with intra-amniotic infection/inflammation, but not in those without intra-amniotic infection/inflammation (after adjusting for gestational age and antenatal corticosteroid administration). Conclusion: A new antibiotic combination consisting of ceftriaxone, clarithromycin, and metronidazole prolonged the latency period, reduced acute histologic chorioamnionitis/funisitis, and improved neonatal outcomes in patients with preterm PROM. These findings suggest that the combination of anti-microbial agents (ceftriaxone, clarithromycin, and metronidazole) may improve perinatal outcome in preterm PROM.

Expression of extracellular signal-regulated kinase1/2 and p38 mitogen-activated protein kinase in the invasive trophoblasts at the human placental bed

BACKGROUND Mitogen-activated protein kinases (MAP kinases) participate in signal transduction pathways that control embryogenesis, cell differentiation, cell proliferation and cell death. The roles of extracellular signal-regulated kinase1/2 (ERK1/2) and p38 MAP kinase in the differentiation and invasion of human trophoblasts have been studied. However, the in vivo expression and activation of ERK1/2 and p38 at the placental bed have not been elucidated. METHODS The study group consisted of placental bed biopsy tissues obtained from the pregnancies without preeclampsia (n=24) and with preeclampsia (n=8) between 31 and 40 weeks of gestation. We evaluated the expressions and phosphorylations of ERK1/2 and p38 MAP kinase in the invasive trophoblasts in the placental bed tissues using immunohistochemistry. RESULTS p38 and phospho-p38 MAP kinase were not detected in invasive trophoblasts in cases or controls. ERK1/2 and phospho-ERK1/2 were positive in invasive trophoblasts albeit with variable staining. Phosphorylation of ERK1/2 was significantly less frequent in invasive trophoblasts in placental bed biopsies from women with preeclampsia compared with normotensive controls. CONCLUSION These findings suggest that preeclampsia is associated with decreased activation of ERK1/2 in invasive trophoblasts in vivo.

Ultrasonographic severity scoring of non-immune hydrops: A predictor of perinatal mortality

Abstract Aim: To develop an ultrasonographic severity scoring of non-immune hydrops in order to predict perinatal outcomes in women with non-immune hydrops. Methods: The study population consisted of pregnant women who were admitted and delivered with the diagnosis of fetal non-immune hydrops and singleton gestation. Cases were divided into “perinatal survivor” and “perinatal non-survivor” groups. Perinatal non-survivor cases were defined as those with stillbirth or neonatal death ≤28 completed days after birth. The presence of an abnormal fluid collection in each body compartment, such as subcutaneous edema, pleural effusion, pericardial effusion, or ascites was assigned a score of 1 point per each body compartment, and the absence of abnormal fluid collection was scored as 0 point. The total number of abnormal fluid collections was converted to a numeric score, which was called the ultrasonographic severity scoring of non-immune hydrops (USNIH). Results: Perinatal death occurred in 46.5% (20/43) of the cases of non-immune hydrops. USNIH in patients of the non-survivor group was significantly higher than that in those of the survivor group [non-survivor group 3 (2–4) vs. survivor 2 (2–3); median (range); P<0.05]. Perinatal mortality rates were higher in patients with USNIH ≥3 points than in those with USNIH of 2 points (67% vs. 13%, P<0.005). This difference remained significant after adjustment for confounding variables. When confining analysis to those with idiopathic non-immune hydrops, women in the perinatal non-survivor group had significantly higher USNIH score than those in the perinatal survivor group, and this difference remained significant after adjustment. Conclusions: Our USNIH system may be a reliable predictive marker for perinatal outcomes in cases of non-immune hydrops, especially in idiopathic hydrops during the antenatal period.

Secreted phospholipase A2 is increased in meconium-stained amniotic fluid of term gestations: potential implications for the genesis of meconium aspiration syndrome

Abstract Background: Meconium-stained amniotic fluid (MSAF) represents the passage of fetal colonic content into the amniotic cavity. Meconium aspiration syndrome (MAS) is a complication that occurs in a subset of infants with MSAF. Secreted phospholipase A2 (sPLA2) is detected in meconium and is implicated in the development of MAS. The purpose of this study was to determine if sPLA2 concentrations are increased in the amniotic fluid of women in spontaneous labor at term with MSAF. Materials and methods: This was a cross-sectional study of patients in spontaneous term labor who underwent amniocentesis (n = 101). The patients were divided into two study groups: (1) MSAF (n = 61) and (2) clear fluid (n = 40). The presence of bacteria and endotoxin as well as interleukin-6 (IL-6) and sPLA2 concentrations in the amniotic fluid were determined. Statistical analyses were performed to test for normality and bivariate analysis. The Spearman correlation coefficient was used to study the relationship between sPLA2 and IL-6 concentrations in the amniotic fluid. Results: Patients with MSAF have a higher median sPLA2 concentration (ng/mL) in amniotic fluid than those with clear fluid [1.7 (0.98–2.89) versus 0.3 (0–0.6), p < 0.001]. Among patients with MSAF, those with either microbial invasion of the amniotic cavity (MIAC, defined as presence of bacteria in the amniotic cavity), or bacterial endotoxin had a significantly higher median sPLA2 concentration (ng/mL) in amniotic fluid than those without MIAC or endotoxin [2.4 (1.7–6.0) versus 1.7 (1.3–2.5), p < 0.05]. There was a positive correlation between sPLA2 and IL-6 concentrations in the amniotic fluid (Spearman Rho = 0.3, p < 0.05). Conclusion: MSAF that contains bacteria or endotoxin has a higher concentration of sPLA2, and this may contribute to induce lung inflammation when meconium is aspirated before birth.

Identification and characterization of proteins in amniotic fluid that are differentially expressed before and after antenatal corticosteroid administration

OBJECTIVE We sought to examine changes in the intraamniotic proteomic environment after the administration of antenatal corticosteroids to women with impending preterm delivery. STUDY DESIGN Amniotic fluid samples were collected at the time of clinically indicated amniocentesis before and within 7 days of administration of antenatal corticosteroids for impending preterm delivery (n = 12). Proteins differentially expressed before and after corticosteroids were identified by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. They were isolated, characterized, and quantified by fast protein liquid chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in-gel tryptic digestion, immunodepletion assays, enzyme-linked immunosorbent assay, and electrospray ionization tandem mass spectrometry. RESULTS Five protein peaks of interest were identified and characterized, all of which were significantly decreased after antenatal corticosteroid administration. These included 2 isoforms of transthyretin, albumin, prothrombin fragment 2, and lumican. CONCLUSION Four proteins, identified and characterized in amniotic fluid, were differentially expressed with antenatal corticosteroid administration. These data may provide additional insight into the molecular mechanisms by which antenatal corticosteroids prevent neonatal complications.

Expression changes of proteins associated with the development of preeclampsia in maternal plasma: A case‐control study

Defective deep placentation, involving abnormal transformation of the spiral arteries in the junctional zone of the myometrium, is known to cause significant obstetric complications, such as preeclampsia (PE), fetal growth restriction, and placental infarction leading to fetal death. Serological biomarkers to predict and diagnose PE would help antenatal care and reduce obstetric complications. To discover candidate PE biomarkers, we first performed global proteomic profiling of three pairs of plasma samples obtained from pregnant women in the early second trimester, who subsequently developed PE, and controls to identify candidate proteins that were abundant in the patients. We further evaluated the changes in the expression of PE‐representing proteins in stored plasma samples of a cohort that subsequently developed PE and their matched controls by MRM‐MS analysis. We identified that both complement C1s subcomponent (C1S) and protein AMBP were elevated in the plasma samples of the PE cohort before the manifestation of clinical disease. We propose that these proteins may be involved in the remodeling process of the spiral arteries even before PE manifestation. These proteins can serve as potential plasma biomarkers to predict the pregnant women having an increased risk of developing PE.