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

Abstract

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 case-control 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 a white blood cell count >20 cells/mm3 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) 32–37.3 weeks vs. 38.0 weeks, IQR 35–40 weeks, respectively; p=0.018]. 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; p=0.029]. Similar results were observed for delivery at <37 weeks [Cases: 70% (7/10) vs. Controls: 36% (18/50); p=0.046]. 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.

A molecular signature of an arrest of descent in human parturition

“…However, normal spontaneous human parturition is also characterized by an inflammatory response, 143;144;149;150;153;154;161;163-192 partially attributed to a massive influx of leukocytes into myometrium at the onset of term labor 7786;193 Interestingly, our findings indicate that the molecular signature of an arrest of descent in comparison to spontaneous term labor involves a further overexpression of genes involved in inflammation.…”

Placental bed disorders in preterm labor, preterm PROM, spontaneous abortion and abruptio placentae

“…The spectrum of the phenotype may range from cervical insufficiency, preterm labor with intact membranes or preterm PROM. The causes of spontaneous preterm parturition have been proposed to include infection/inflammation, 14–26 ischemia due to vascular disease, 27;28 cervical disease, 29–31 uterine overdistension, 32 abnormal allograft reaction, 33;34 allergy, 35–37 and endocrine disorders (deficient progesterone action). 38–41 Growing evidence suggests that vascular disorders may play a role in a subset of patients who have preterm labor with intact membranes or preterm PROM.…”

Immune Regulation in Pregnancy

“…Interactions between mast cells and other cells at the maternal-fetal interface mediate implantation(H 2 R) 42 support angiogenesis 43, 44 , and preserves quiescence 45 until-term when histamine from mast cells binds to H 1 R and fosters uterine contractions 46, 47,48 . Type I sensitivity induces premature labor in humans 49 and in n animals 50 via histamine binding to H 1 R in the uterus 51 .…”