Progesterone increases blood pressure in spontaneous gestational hypertension in rats.

Background: Gestational hypertensive disorders are a leading cause of maternal mortality in the US, accounting for up to 10% of these deaths. During pregnancy, a new rat model (SHHF rat) has been shown to develop spontaneous hypertension with increases of more than 40 mm Hg systolic blood pressure (BP), which resolves after delivery, and which lead us to ask whether the hypertension may be triggered by increased levels of progesterone in these rats.

Methods: To test this hypothesis, groups of SHHF rats were treated with progesterone (PROG), estrogen (EST), or progesterone and estrogen (PROG+EST) that correspond to levels that occur during pregnancy.