To study the relationship between somatostatin (SS), atrial natriuretic peptide (ANP), beta-endorphin (beta-EP), aldosterone (Aldo) and pregnancy induced hypertension (PIH), blood was collected from 69 cases, including non-pregnant women, normal pregnant women, patients with PIH and their newborns (umbilical arteries) and plasma levels of ANP, SS, beta-EP, Aldo were measured by radioimmunoassay. Results indicated that ANP, SS beta-EP and Aldo levels either during normal pregnancy or at delivery were significantly higher than those in non-pregnant women. ANP, SS and beta-EP levels in last trimester of patients with PIH, particular in severe cases, were significantly higher than those in normal pregnancy or moderate PIH whereas Aldo levels were lower in PIH when compared with normal pregnancy. A positive correlation between ANP, SS levels and the severity of PIH was observed. Levels of ANP, SS, beta-EP and Aldo in newborns were higher than those in mothers at delivery. Levels of ANP and SS in neonates born to mother of PIH were much higher, whereas beta-EP and Aldo were lower as compared with normal pregnancy. The conclusion is that high levels of ANP and Aldo during pregnancy may play an important role in stabilizing blood pressure and maintaining the balance of water and electrolyte. Therefore it could be used as an index for prediction of PIH.