Parity and Hypertension.

Among the many physiological factors which have been hypothesized as associated with elevated blood pressure levels and increased incidence of hypertension, the possible effect of pregnancy in the production of these conditions has proven to be among the more elusive to quantitate and evaluate. At the same time, the possible association is among the more interesting from an epidemiological standpoint, not only because of the importance of the primal question of whether or not pregnancy is a factor in the etiology of hypertension, but also because of the component parts represented by those pregnancies complicated by preeclampsia. Age is considered by many observers to be an important factor in the production of residual hypertension, and the statistical association of age with increased blood pressure levels is probably the most pronounced and easily demonstrated phenomenon observable in any study population. A moderate decline in average diastolic blood pressure among the general population after age 55 is an exception to this, and is less frequently evaluated. Body measurements, race, and several other variables may be cited as also being correlated with blood pressure levels, however, their effect is much less significant than that observable for age.