We determined plasma human atrial natriuretic peptide (hANP) levels in normal pregnancy and pregnancy induced hypertension (PIH). The plasma hANP levels slightly decreased in the first trimester of normal pregnancy and tended to recover as pregnancy advanced, although these changes were slight. However, the plasma hANP level in puerperium was higher than that in the third trimester of normal pregnancy. The plasma hANP level in mild PIH was not significantly higher than that in the third trimester of normal pregnancy. In contrast, the plasma hANP level in three cases of severe PIH was approximately 200% higher than those in the normal third trimester and mild PIH.</p
