[Serial changes of atrial natriuretic peptide and brain natriuretic peptide during cesarean section under spinal anesthesia].

Both atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are considered to play a role in regulation of body fluid volume and blood pressure. Serial changes of their plasma concentrations are known to reflect blood volume. In this study, we investigated the serial changes in maternal blood concentrations of ANP and BNP in those who underwent cesarean section under spinal anesthesia. Blood samples were obtained before anesthesia, before surgery, at the end of surgery, and on the next morning. Samples were also compared with those from normal pregnant women. Throughout the cesarean section, ANP did not show any significant changes, while BNP remained within normal ranges during anesthesia and increased on the next morning. We concluded that ANP and BNP were regulated differentially, and that BNP reflected blood volume significantly during and after spinal anesthesia.