Atrial natriuretic peptide in transient puerperal hypertension

This study is the first approach to evaluate whether human atrial natriuretic peptide (hANP) is involved in the pathophysiology in transient puerperal hypertension (TPH). Five women who were normotensive throughout pregnancy, labor, and delivery developed hypertension between the first and sixth postpartum day. hANP (pg/ml) and plasma renin activity (PRA, ng/ml/h), angiotensin I, II (AI, II, pg/ml), and aldosterone (Aldo, pg/ml) in plasma were quantified by radioimmunoassay. Ten women without hypertension were also studied on hANP, PRA, AI, AII, and Aldo sequentially as the control group. hANP was apparently lower in women with TPH than in normotensive women. The levels of PRA, AI, AII, and Aldo were also clearly decreased in women with TPH, whereas those values in normotensive women were not altered from nonpregnant levels. Maternal natriuresis usually reaches the peak at 3-5 days postpartum. The decrease of hANP and PPA, AI, AII, and Aldo in TPH coincides with this natriuretic period. This observation suggests that hANP may serve an important role in the pathogenesis of TPH.