Atrial natriuretic peptide concentrations in umbilical cord plasma from pre-eclamptic women

Summary. Atrial natriuretic peptide (ANP) was measured in arterial and venous umbilical cord plasma at the time of delivery by cesarean section in pre-eclamptic (n= 7) and normal women (n= 6). In addition venous samples were obtained from pre-eclamptic (n= 7) and normal pregnant women (n= 7) near term. ANP plasma levels were higher in pregnant women with pre-eclampsia than in normal pregnant women (27·9±4·4 [mean±SEM] and 14·1 ±2·5 pmol 1^-1, respectively, P<0·05). Immediately after delivery plasma ANP in pre-eclamptic mothers was 66·7 ± 12·8 pmol 1^-1 compared to 13·9 ±2·2 pmol 1^-1 in normal mothers (P<0·01). However, in the pre-eclamptic group the levels of ANP in arterial and venous umbilical cord plasma (19·5 ±4·2 and 16·7±4·3 pmol 1^-1 respectively) were significantly (P<0·01) lower than ANP levels in arterial and venous cord plasma (39·6 ± 1·0 and 31·1±4·2 pmol 1^-1, respectively) from normal mothers. It is concluded that the increased ANP plasma level in pre-eclamptic women originates from a maternal source. In addition, since the ANP level is lower in cord plasma than in maternal plasma in pre-eclampsia, fetoplacental volume homeostasis may also be changed in pre-eclampsia.