Atrial natriuretic factor concentrations during pregnancy and in the postpartum period.
Atrial natriuretic factor (ANF) is a hormone that regulates fluid and electrolyte homeostasis. Increased intra-atrial pressure or atrial distention, which might occur secondary to intravascular volume expansion, stimulate the secretion of ANF by human atrial myocytes. During normal human pregnancy, there is a progressive increase in total intravascular fluid volume. Thus, we asked the following question: Does this physiologic adaptation to pregnancy result in an increase in ANF concentrations? Concentrations of alpha-human ANF (alpha-hANF) were measured by a specific radioimmunoassay in venous blood samples obtained longitudinally in the first, second, and third trimesters of pregnancy, during the intrapartum period, in the early postpartum period, and 6 to 8 weeks postpartum from 11 normal women who had no antepartum, intrapartum, or postpartum complications. Maternal circulating alpha-hANF levels were not different from those seen in the nonpregnant state. However, higher alpha-hANF concentrations were noted in the early postpartum period. Although the hypervolemia of normal pregnancy is not associated with higher alpha-hANF concentrations, other possibilities (such as increased ANF clearance, dilutional effects) need to be investigated. Finally, the etiology for the transient increase in alpha-hANF levels in the early postpartum period remains to be elucidated.
Hatjis
C G
CG
Department of Obstetrics and Gynecology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina.
Kofinas
A D
AD
Greelish
J P
JP
Swain
M
M
Rose
J C
JC
D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D049590:Postpartum Period / Q000097:blood*; D011247:Pregnancy / Q000097:blood*
D009320:Atrial Natriuretic Factor