The effects of delivery route and anesthesia type on early postnatal weight loss in newborns: the role of vasoactive hormones.

OBJECTIVE: To investigate the effects of delivery route and maternal anesthesia type and the roles of vasoactive hormones on early postnatal weight loss in term newborns.

METHODS: Ninety-four term infants delivered vaginally (group 1, n=31), cesarean section (C/S) with general anesthesia (GA) (group 2, n=29), and C/S with epidural anesthesia (EA) (group 3, n=34) were included in this study. All infants were weighed at birth and on the second day of life and intravenous (IV) fluid infused to the mothers for the last 6 h prior to delivery was recorded. Serum electrolytes, osmolality, N-terminal proANP (NT-proANP), brain natriuretic peptide (BNP), aldosterone and plasma antidiuretic hormone (ADH) concentrations were measured at cord blood and on the second day of life.

RESULTS: Our research showed that postnatal weight loss of infants was higher in C/S than vaginal deliveries (5.7% vs. 1.3%) (p < 0.0001) and in EA group than GA group (6.8% vs. 4.3%) (p < 0.0001). Postnatal weight losses were correlated with IV fluid volume infused to the mothers for the last 6 h prior to delivery (R = 0.814, p = 0.000) and with serum NT-proANP (R = 0.418, p = 0.000), BNP (R = 0.454, p = 0.000), and ADH (R = 0.509, p = 0.000) but not with aldosterone concentrations (p > 0.05).

CONCLUSION: Large amounts of IV fluid given to the mothers who were applied EA prior to the delivery affect their offsprings' postnatal weight loss via certain vasoactive hormones.