Characterization of amniotic fluid sludge in preterm and term gestations

Juan Pedro Kusanovic, Eunjung Jung, Roberto Romero, Pooja Mittal Green, Chia Ling Nhan-Chang, Edi Vaisbuch, Offer Erez, Chong Jai Kim, Luis F. Gonçalves, Jimmy Espinoza, Shali Mazaki-Tovi, Tinnakorn Chaiworapongsa, Ramiro Diaz-Primera, Lami Yeo, Manaphat Suksai, Francesca Gotsch, Sonia S. Hassan

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


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.

Original languageEnglish
Pages (from-to)9770-9779
Number of pages10
JournalJournal of Maternal-Fetal and Neonatal Medicine
Issue number25
StatePublished - 1 Jan 2022
Externally publishedYes


  • Amniocentesis
  • congenital dermatitis
  • intra-amniotic infection
  • meconium
  • vernix

ASJC Scopus subject areas

  • Obstetrics and Gynecology
  • Pediatrics, Perinatology, and Child Health


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