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.

Lee SM, et al. J Korean Med Sci. 2020 May;35(26):e198. https://doi.org/10.3346/jkms.2020.35.e198

No information exists about whether fetal inflammatory-response(FIR), early-onset neonatal sepsis(EONS) and chorioamnionitis(an advanced-stage of maternal inflammatory-response in extraplacental membranes) continuously increase according to the progression of inflammation in umbilical-cord(UC). The objective of current-study is to examine this-issue. Study-population included 239singleton pregnant-women(gestational-age[GA] at delivery: 21.6~36weeks) who had inflammation in extraplacental membranes or chorionic plate (CP) and either preterm-labor or preterm-PROM. We examined FIR, and the frequency of fetal inflammatory-responses syndrome(FIRS), proven-EONS, suspected-EONS and chorioamnionitis according to the progression of inflammation in UC. The progression of inflammation in UC was divided with a slight-modification from previously reported-criteria as follows: stage0, inflammation-free UC; stage-1: umbilical phlebitis only; stage-2: involvement of at least one UA and either the other UA or UV without extension into WJ; stage-3: the extension of inflammation into WJ. FIR was gauged by umbilical-cord-plasma(UCP) CRP concentration(ng/ml) at birth, and FIRS was defined as an elevated UCP CRP concentration at birth(≥200ng/ml). Stage-0, stage-1, stage-2 and stage-3 of inflammation in UC were present in 48.1%, 15.5%, 6.7%, and 29.7% of cases. FIR continuously increased according to the progression of inflammation in UC(Kruskal-Wallis test,P<0.001; Spearman-rank-correlation test,P<0.000001,r = 0.546). Moreover, there was a significant and stepwise increase in the frequency of FIRS, proven-EONS, suspected-EONS and chorioamnionitis according to the progression of inflammation in UC(each for P<0.000005 in both chi-square test and linear-by-linear-association). Multiple logistic-regression analysis demonstrated that the more advanced-stage in the progression of inflammation in UC(i.e., stage-1 vs. stage-2 vs. stage-3), the better predictor of suspected-EONS (Odds-ratio[OR]3.358, 95%confidence-interval[CI]:1.020–11.057 vs. OR5.147, 95%CI:1.189–22.275 vs. OR11.040, 95%CI:4.118–29.592) and chorioamnionitis(OR6.593, 95%CI:2.717–15.999 vs. OR16.508, 95%CI:3.916–69.596 vs. OR20.167, 95%CI:8.629–47.137). FIR, EONS and chorioamnionitis continuously increase according to the progression of inflammation in UC among preterm-gestations with inflammation in extraplacental membranes or CP. This finding may suggest that funisitis(inflammation in UC) is both qualitatively and quantitatively histologic-counterpart of FIRS, and a surrogate-marker for chorioamnionitis.

Objective Although intra-amniotic(IA) infection is present in both preterm labor and intact membranes(PTL) and preterm premature rupture of membranes(preterm-PROM), it is more common in preterm-PROM than in PTL. Microorganisms and their products in the amniotic-cavity can elicit an inflammatory-response in fetus as well as in amniotic-cavity in the progression of acute histologic chorioamnionitis(acute-HCA). A fundamental question is whether a fetal and an IA inflammatory-response is more severe in preterm-PROM than in PTL, in the same-context of acute-HCA with or without fetal-involvement. The purpose of current-study was to answer this-question. Study-Design Study population consisted of 213 singleton preterm-gestations(<34 weeks) delivered within 4 days of amniocentesis due to PTL(120 cases) or preterm-PROM(93 cases). The intensity of fetal and IA inflammatory-responses was compared between PTL and preterm-PROM, according to placental inflammatory conditions:1)placenta without inflammatory-lesion;2)acute-HCA without funisitis;3)acute-HCA with funisitis. IA inflammatory response was assessed by amniotic-fluid(AF) matrix metalloproteinase-8(MMP-8), and fetal inflammatory response(FIR) by umbilical-cord plasma(UCP) C-reactive protein(CRP) at birth. Results 1) Patients with preterm-PROM had higher rates of IA infection, acute-HCA, and acute-HCA with funisitis than those with PTL did( p <.01 for each);2) there were no significant differences in the intensity of fetal and IA inflammatory-responses and the rate of cervical dilatation≥3 cm or 4 cm between patients with PTL and those with preterm-PROM in the context of both placenta without inflammatory-lesion and acute-HCA without funisitis( p >.05 for each);3) however, acute-HCA with funisitis was associated with a significantly higher median AF MMP-8 and UCP CRP concentration and higher rate of cervical dilatation≥3 cm or 4 cm in PTL than in preterm-PROM(AF MMP-8, 675 ng/mlvs.417 ng/ml; UCP CRP, 969 ng/mlvs.397 ng/ml;each for p <.05), despite less common IA infection in PTL than in preterm-PROM(29%vs.57%; p <.05). Conclusions A fetal and an IA inflammatory-response is more severe in PTL than in preterm-PROM in the context of funisitis, despite less common IA infection. This unexpected observation may indicate the fundamental difference in the pathogenesis between PTL and preterm-PROM.

Park CW, et al. Obstet Gynecol Sci. 2013 May;56(3):167-175. http://dx.doi.org/10.5468/ogs.2013.56.3.167

S Objective: We propose that an elevated maternal serum C-reactive protein (CRP) concentration in the context of intra-amniotic inflammation (IAI) is a predictor for amnionitis development, known to be the most advanced stage of maternal inflammatory response during the progression of acute histologic chorioamnionitis in preterm gestations. Methods: Study population consisted of 53 singleton gestations with IAI, who underwent amniocentesis due to preterm labor and intact membranes (PTL) and delivered preterm-neonates (<34.5 weeks) within 5 days of amniocentesis. The frequency of amnionitis and the intensity of fetal and amniotic fluid (AF) inflammatory response were examined according to the presence or absence of an elevated maternal serum CRP (≥0.7 mg/dL) at the time of amniocentesis. IAI was defined as an elevated AF matrix metalloproteinase-8 (MMP-8) (≥23 ng/mL), and fetal inflammatory response syndrome (FIRS) defined as an elevated umbilical cord plasma CRP (≥200 ng/mL). Results: (1) Patients (73.6%, 39/53) with an elevated maternal serum CRP had a significantly higher rate of amnionitis (59.0% versus 7.1%; p < 0.005), but not funisitis (46.2% versus 28.6%; p > 0.05), and higher median AF MMP-8 and umbilical cord plasma CRP concentration at birth than patients (26.4%,14/53) without that (AF MMP-8 (ng/mL): 373.1 versus 138.6: p = 0.05; umbilical cord plasma CRP (ng/mL): 363.4 versus 15.5: p < 0.05); (2) Multiple logistic regression analysis demonstrated that an elevated maternal serum CRP was a better independent predictor of amnionitis (odds ratio (OR), 12.5: 95% confidence interval (CI), 1.1–141.0; p < 0.05) than FIRS (OR, 3.6: 95% CI, 0.6–20.2; p = 0.150) and any other AF tests. Conclusions: An elevated maternal serum CRP concentration in the context of IAI is an indicator that the development of amnionitis, an intense fetal and AF inflammatory response are likely in patients with PTL.