Spiral Artery Morphology in Pregnancies Complicated by Chronic Hypertension: the Relation to Antihypertensive Therapy and to Superimposed Preeclampsia

Abstract

Objective: To study the morphological changes in spiral arteries in chronic hypertensive pregnancies, in both antihypertensive treated and non-treated women, and also in women who remain hypertensive only or develop superimposed preeclampsia.

Methods: A retrospective study of placental bed biopsies containing at least one spiral artery, taken at cesarean section from 20 women with chronic hypertension. Thirteen of the 20 women were treated with antihypertensive agents and 11 of the 20 women developed superimposed preeclampsia (7 of these were taking antihypertensive drugs). The morphological features of the spiral arteries were reviewed in relation to antihypertensive treatment and to the development of superimposed preeclampsia.

Results: Twenty-two decidual and 56 myometrial spiral arteries were studied. In both the antihypertensive treated and the nontreated women, the commonest decidual spiral artery feature was acute atherosis. In the myometrial segments the incidence of disorganization, hyperplasia, and atherosis was not reduced, nor was physiological change increased by antihypertensive therapy. Acute atherosis and lack of physiological change in myometrial segments of the spiral arteries were both significantly (P < 0.05) more frequent in those women who developed superimposed preeclampsia than in those who did not.

Conclusions: Antihypertensive therapy in pregnancies complicated by chronic hypertension was not associated with more physiological spiral artery adaptation. The development of superimposed preeclampsia was associated with more severe spiral artery vasculopathy characterized by reduced physiological change and increased atherosis.

Key Words:

• Antihypertensive therapy
• Chronic hypertension
• Spiral artery