The clinical significance of eosinophils in the amniotic fluid in preterm labor

Roberto Romero, Juan Pedro Kusanovic, Ricardo Gomez, Ronald Lamont, Egle Bytautiene, Robert E. Garfield, Pooja Mittal, Sonia S. Hassan, Lami Yeo

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Objective.White blood cells are not traditionally considered to be normally present in amniotic fluid. This study was conducted after the observation that a patient with preterm labor and intact membranes had eosinophils as a predominant cell in the amniotic fluid, and had an episode of asthma during the index pregnancy. The goal of this study was to determine whether women presenting with preterm labor with eosinophils in the amniotic fluid had a different outcome than those without eosinophils as the predominant white blood cell in the amniotic cavity. Methods.This retrospective casecontrol study included women who presented with preterm labor and intact membranes between 24 and 34 weeks of gestation. Patients underwent an amniocentesis shortly after admission for the assessment of the microbiologic status of the amniotic cavity and/or fetal lung maturity. Amniotic fluid was cultured for aerobic and anaerobic bacteria as well as genital mycoplasmas. Cytologic studies included amniotic fluid white blood cell count and differential, which was performed on cytocentrifuged specimens. Patients with microbial invasion of the amniotic cavity and/or an amniotic fluid white blood cell count >20 cells/mm 3 were excluded from the study. Cases were defined as women in whom the differential contained >20 of eosinophils. Controls were selected among women with an amniotic fluid eosinophil count ≤20 and matched for gestational age at amniocentesis. The analysis was conducted with non-parametric statistics. Results.The study population consisted of 10 cases and 50 controls. Gestational age and cervical dilatation at admission were similar in both groups. Cases had a lower gestational age at delivery than controls [34.6 weeks, inter-quartile range (IQR) 3237.3 weeks vs. 38.0 weeks, IQR 3540 weeks, respectively; p0.018]. The prevalence of preterm delivery ≤35 weeks was higher among patients who had >20 eosinophils than in the control group [50 (5/10) vs. 18 (9/50), respectively; p0.029]. Similar results were observed for delivery at <37 weeks [cases: 70 (7/10) vs. controls: 36 (18/50); p0.046]. Conclusions.Women with preterm labor and intact membranes who have a large proportion of eosinophils in the amniotic fluid are at an increased risk for spontaneous preterm delivery. These patients may have had an episode of preterm labor related to a type I hypersensitivity reaction.

Original languageEnglish (US)
Pages (from-to)320-329
Number of pages10
JournalJournal of Maternal-Fetal and Neonatal Medicine
Issue number4
StatePublished - Apr 2010
Externally publishedYes


  • Allergy
  • Allergy-induced preterm labor
  • Amniotic fluid cells
  • Amniotic fluid white blood cells
  • Atopy
  • Labor
  • Mast cells
  • Parturition
  • Pregnancy
  • Premature birth
  • Premature labor
  • Prematurity
  • Preterm birth
  • Type I hypersensitivity reaction

ASJC Scopus subject areas

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


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