title: Electrical impedance spectroscopy of the cervix in non-pregnant and pregnant women.
abstract: OBJECTIVE
  We sought to validate and measure the electrical impedance of the uterine cervix in non-pregnant and pregnant women by spectroscopy.
  
  
  METHODS
  Cervical stromal impedance (CSI) was measured in 50 non-pregnant, 20 1st, 20 2nd and 50 3rd trimester pregnant women. The technique was also validated by comparing in vivo data to a finite element (FE) model of cervical tissue.
  
  
  RESULTS
  CSI agreed well with the FE model and was highly reproducible in all study groups. Mean (S.E.) CSI at 4-819 kHz was higher in pregnant (2.78 +/- 0.09 Omega m) compared to non-pregnant (2.38 +/- 0.07, p < 0.01) women, and in the 3rd trimester (3.08 +/- 0.13) compared to non-pregnant (p < 0.01), 1st trimester (2.42 +/- 0.12, p < 0.001) and 2nd trimester (2.20 +/- 0.05, p < 0.001) pregnant women.
  
  
  CONCLUSIONS
  Measurement of CSI provides a non-invasive method of assessing cervical tissue characteristics. Cervical extracellular matrix synthesis and leukocyte infiltration may account for the increased tissue impedance noted in the 3rd trimester.
authors.affiliation: Academic Unit of Reproductive and Developmental Medicine, University of Sheffield, Sheffield Teaching Hospitals NHS Trust, Sheffield, United Kingdom.
authors.forename: Saurabh V
authors.initials: SV
authors.lastname: Gandhi
authors.forename: Dawn
authors.initials: D
authors.lastname: Walker
authors.forename: Pete
authors.initials: P
authors.lastname: Milnes
authors.forename: Soma
authors.initials: S
authors.lastname: Mukherjee
authors.forename: Brian H
authors.initials: BH
authors.lastname: Brown
authors.forename: Dilly O C
authors.initials: DO
authors.lastname: Anumba
mesh_terms: D000293:Adolescent; D000328:Adult; D020070:Cervical Ripening / Q000502:physiology*; D002584:Cervix Uteri / Q000033:anatomy & histology / Q000502:physiology*; D003094:Collagen / Q000502:physiology; D017097:Electric Impedance; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D003094:Collagen