Venous distensibility during pregnancy determined by graded venous congestion.

The increase in volume of the human calf and forearm during pregnancy resulting from graded venous congestion has been measured plethysmographically in the raised leg and forearm of 10 recumbent subjects during and after pregnancy. Normal pressure volume curves were determined and the alterations in this curve over the various stages of gestation were presumed to indicate an alteration in the distensibility of the capacity blood vessels. This distensibility was found to increase with the progression of pregnancy in both the forearm and the calf particularly after the thirtieth week of pregnancy. The distensibility, however, appeared to return to below the 10 week gestation level at the eighth postpartum week. The increase in distensibility was greater in the calf than in the forearm although both were significantly increased.