Association of amniotic fluid sludge with preterm labor and histologic chorioamnionitis in pregnant Japanese women with intact membranes: A retrospective study

Amniotic Sludge and Prematurity: Systematic Review and Meta-analysis

OBJECTIVE

 To perform a systematic review and meta-analysis of studies on maternal, fetal, and neonatal outcomes of women with singleton pregnancies, after spontaneous conception, and with the diagnosis of amniotic sludge before 37 weeks of gestational age.

DATA SOURCES

 We conducted a search on the PubMed, Cochrane, Bireme, and Theses databases until June 2022.

SELECTION OF STUDIES

 Using the keywords intra-amniotic sludge or fluid sludge or echogenic particles, we found 263 articles, 132 of which were duplicates, and 70 were discarded because they did not meet the inclusion criteria.

DATA COLLECTION

 The articles retrieved were analyzed by 2 reviewers; 61 were selected for full-text analysis, 18 were included for a qualitative analysis, and 14, for a quantitative analysis.

DATA SYNTHESIS

 Among the maternal outcomes analyzed, there was an increased risk of preterm labor (95% confidence interval [95%CI]: 1.45-2.03), premature rupture of ovular membranes (95%CI: 1.99-3.79), and clinical (95%CI: 1.41-6.19) and histological chorioamnionitis (95%CI: 1.75-3.12). Regarding the fetal outcomes, there was a significant increase in the risk of morbidity (95%CI: 1.80-3.17), mortality (95%CI: 1.14-18.57), admission to the Neonatal Intensive Care Unit (NICU; 95%CI: 1.17-1.95), and neonatal sepsis (95%CI: 2.29-7.55).

CONCLUSION

 The results of the present study indicate that the presence of amniotic sludge is a risk marker for preterm delivery. Despite the heterogeneity of the studies analyzed, even in patients with other risk factors for prematurity, such as short cervix and previous preterm delivery, the presence of amniotic sludge increases the risk of premature labor. Moreover, antibiotic therapy seems to be a treatment for amniotic sludge, and it may prolong pregnancy.

Characterization of amniotic fluid sludge in preterm and term gestations

OBJECTIVE

To describe the characteristics of amniotic fluid sludge obtained from patients in term and preterm gestations.

METHODS

This cross-sectional study included patients with dense aggregates of particulate matter detected in amniotic fluid, observed with transvaginal sonography. All patients were in labor and had an impending delivery, either preterm or at term. Echogenic material contained within amniotic fluid was retrieved transvaginally by needle amniotomy under direct visualization. The amniotic fluid analysis consisted of a Gram stain, cultures for aerobic/anaerobic bacteria and genital mycoplasmas, and a white blood cell count.

RESULTS

Twenty-five patients ranging from 18 to 41 weeks of gestation were included in the study. We observed the following: (1) the appearance of amniotic fluid was consistent with pus-like material, vernix, or meconium by naked eye examination; (2) samples collected before 33 weeks of gestation (n = 13) had a pus-like appearance; however, after this gestational age, most of the samples [83% (10/12)] appeared to be consistent with vernix; (3) amniotic fluid cultures were positive for microorganisms in 13 patients, of which 10 were preterm gestations before 33 weeks; (4) the most frequent microorganisms retrieved by culture were genital mycoplasmas (Ureaplasma urealyticum [46% (6/13)]), followed by Mycoplasma hominis [31% (4/13)] and Candida albicans [15% (2/13)]; and (5) patients with sonographic particulate matter in preterm gestations frequently presented acute histologic chorioamnionitis and funisitis, but these conditions were rare in patients at term.

CONCLUSION

The nature of amniotic fluid particulate material varies as a function of gestational age. The material obtained in preterm gestations is frequently related to an inflammatory process, while that obtained at term is often consistent with vernix and appears to represent a maturational process.

Labor dystocia and risk of histological chorioamnionitis and funisitis: a study from a single tertiary referral center

Background

Intrauterine inflammation affects short- and long-term neonatal outcomes. Histological chorioamnionitis and funisitis are acute inflammatory responses in the fetal membranes and umbilical cord, respectively. Although labor dystocia includes a potential risk of intrauterine inflammation, the risk of histological chorioamnionitis and funisitis of labor dystocia has not been evaluated yet. This study aimed to examine the association between labor dystocia and risk of histological chorioamnionitis and funisitis.

Methods

In this retrospective cohort study, the cases who underwent histopathological examinations of the placenta and umbilical cord at Fukushima Medical University Hospital, Japan, between 2015 and 2020, were included. From the dataset, the pathological findings of the patients with labor dystocia and spontaneous preterm birth were reviewed. Based on the location of leukocytes, the inflammation in the placenta (histological chorioamnionitis) and umbilical cord (funisitis) was staged as 0–3. Multiple logistic regression analysis was performed to evaluate the risk of histological chorioamnionitis, histological chorioamnionitis stage ≥2, funisitis, and funisitis stage ≥2.

Result

Of 317 women who met the study criteria, 83 and 144 women had labor dystocia and spontaneous preterm birth, respectively, and 90 women were included as controls. Labor dystocia was a risk factor for histological chorioamnionitis (adjusted odds ratio, 6.3; 95% confidential interval, 1.9–20.5), histological chorioamnionitis stage ≥2 (adjusted odds ratio, 6.0; 95% confidence interval, 1.7–21.8), funisitis (adjusted odds ratio, 15.4; 95% confidence interval, 2.3–101.3), and funisitis stage ≥2 (adjusted odds ratio, 18.5; 95% confidence interval, 2.5–134.0). Spontaneous preterm birth was also a risk factor for histological chorioamnionitis (adjusted odds ratio, 3.7; 95% confidence interval, 1.7–7.8), histological chorioamnionitis stage ≥2 (adjusted odds ratio, 3.0; 95% confidence interval, 1.2–7.9), and funisitis (adjusted odds ratio, 6.6; 95% confidence interval, 1.4–30.6). However, the adjusted odds ratio was smaller in spontaneous preterm births than in labor dystocia.

Conclusion

Labor dystocia is a risk factor for severe histological chorioamnionitis and funisitis. Further studies are required to evaluate the effects of histological chorioamnionitis and funisitis on long-term neonatal outcomes.