Physical properties of the chorioamnion throughout gestation.
OBJECTIVE
Our purpose was to assess the tensile strength of the chorioamnion at various gestational ages.


METHODS
Segments of chorioamnion were obtained from 35 patients delivered at gestational ages ranging from 17 to 41 weeks. Clinical information including gestational age, chorioamnionitis, premature rupture of membranes, and onset of labor was recorded. Tensile strength (grams to burst and deflection at rupture) was measured on 2 to 16 specimens per patient. Tensile strength of several commercial products was used for comparison.


RESULTS
Tensile strength increases up to 20 weeks of gestation and then plateaus until 39 weeks of gestation, when it falls dramatically. Clinical chorioamnionitis alone did not affect tensile strength, but gross membrane inflammation resulted in reduced tensile strength.


CONCLUSIONS
Tensile strength of the chorioamnion varies with gestational age. This baseline information will be useful in assessing the effects of various conditions and therapies on membrane strength and may provide insight into spontaneous rupture of membranes.
Pressman
Eva K
EK
Division of Maternal Fetal Medicine, University of Rochester Medical Center, NY, USA.
Cavanaugh
Judith L
JL
Woods
James R
JR
D002821:Chorioamnionitis / Q000503:physiopathology; D005321:Extraembryonic Membranes / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D013718:Tensile Strength