High blood pressure lowered by pregnancy

• Published in: The Lancet (British edition) 2000-12, Vol.356 (9246), p.1980-1980
• Main Authors: Murakami, Takehiko, Ogura, Eriko Watanabe, Tanaka, Yuji, Yamamoto, Michiko
• Format: Article
• Language: English
• Subjects: Adenoma - complications; Adrenal Gland Neoplasms - complications; Adult; Biological and medical sciences; Blood Pressure; Case studies; Diseases of mother, fetus and pregnancy; Female; Gynecology. Andrology. Obstetrics; Humans; Hyperaldosteronism - complications; Hyperaldosteronism - physiopathology; Hypertension; Hypertension - complications; Hypertension - physiopathology; Medical sciences; Pregnancy; Pregnancy Complications - physiopathology; Pregnancy. Fetus. Placenta; Puerperal Disorders - complications; Puerperal Disorders - physiopathology
• ISSN: 0140-6736; 1474-547X
• DOI: 10.1016/S0140-6736(00)03311-0

Hypertension and pre-eclampsia is a well known complication of pregnancy. Non-obstetricians often have a misconception that blood pressure usually increases during pregnancy. Presumably, the doctors this patient had seen previously considered that she had no serious underlying diseases to cause hypertension based on the fact that her blood pressure had been normal throughout gestation. However, blood pressure tends to fall during pregnancy in both normotensive and chronically hypertensive women,1,2 and pre-existing hypertension often gets worse after delivery. The history of this patient reminded us that we have to investigate the development of hypertension not only during pregnancy, but also in the puerperium. Pregnant women usually remain normotensive despite striking expansion of blood volume and activation of the renin-angiotensin-aldosterone system. This physiological adaptation is mediated through many mechanisms, including the antagonising action of progesterone on aldosterone and the peripheral vasodilatation caused by various vasorelaxation factors including prostaglandins. However, it is not well understood how blood pressure changes when patients with primary aldosteronism become pregnant. We found three reports of amelioration of hypertension during pregnancy,3-5 whereas there were more reports of women presenting mid-gestation with severe hypertension. One possible explanation for the different clinical presentation is that pregnant women with primary aldosteronism remain normotensive when their plasma aldosterone concentrations are within the pregnancy range and excessive aldosterone action is antagonised by raised progesterone, as is the case with normotensive pregnant women.