The Young's modulus of fetal preterm and term amniotic membranes.
OBJECTIVE
To examine the Young's modulus of the human amniotic membranes, as well as its relationship to gestational age. To determine whether cellular and material-related parameters affect this modulus.


METHODS
In a prospective study at the Obstetric outpatient clinic of the University Hospital Zurich Young's modulus, thickness and mesenchymal:epithelial cell ratio of amniotic membranes of preterm (N=23) and term (N=40) placentae were examined. Significance (P<0.05) was calculated with the Mann-Whitney two-sample rank sum test and Wilcoxon signed rank test, while correlations were made using the Spearman's correlation.


RESULTS
The Young's modulus of preterm amniotic membranes was significantly higher than that of term membranes. It varied within the same amniotic membrane. The thickness of the amnion in both preterm and term membranes did not differ significantly. The thinner the preterm and term amniotic membranes, the higher the Young's modulus was. There was no relation to the mesenchymal:epithelial cell ratio in the amnion.


CONCLUSIONS
Preterm amniotic membranes are stiffer than term amniotic membranes. Tentatively, we hypothesise that there may be a correlation between the extracellular matrix components and the elastic properties of the membrane.
Benson-Martin
Janine
J
Obstetric Research Unit, Department of Obstetrics, University Hospital Zurich, Switzerland.
Zammaretti
Prisca
P
Bilic
Grozdana
G
Schweizer
Thomas
T
Portmann-Lanz
Bettina
B
Burkhardt
Tilo
T
Zimmermann
Roland
R
Ochsenbein-Kölble
Nicole
N
D000650:Amnion / Q000002:abnormalities / Q000033:anatomy & histology* / Q000166:cytology; D004548:Elasticity; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000473:pathology*; D005865:Gestational Age; D006801:Humans; D008962:Models, Theoretical; D010920:Placenta / Q000002:abnormalities / Q000033:anatomy & histology / Q000166:cytology; D011247:Pregnancy; D011379:Prognosis; D011446:Prospective Studies