Passive mechanical properties of the aorta during pregnancy in rats

The passive mechanical properties of the aorta from rats were investigated on in vitro preparations during pregnancy. At 0 mm Hg, volume was found to be higher in pregnancy than in control series. At the lower pressures of the hysteresis curves, Volumetric Distensibility Modulus was higher in control series than during pregnancy. Hysteresis percentage, and stress relaxation were found to be diminished during pregnancy. The water of the aortic wall was increased from the 14th day of pregnancy. This evidence suggests that during pregnancy there was an increase in volume and vessel turgidity, which could be taken in relationship with the lowering of the fibrous elements folds.