Purpose: To evaluate cord blood amino-terminal pro-brain natriuretic peptide (NT-proBNP) levels according to the mode of delivery.
Method: Between 1 March and 31 May 2007, 106 blood samples were drawn from the umbilical vein at the time of delivery. Eighty-four NT-proBNP levels [63 term (34 cesarean sections and 29 vaginal deliveries) and 21 preterm births] were analyzed with respect to gestational age, birth weight, Apgar score, newborn gender, and cord blood pH.
Results: There was no statistical significance on comparison of the mean NT-proBNP values between the cesarean and vaginal delivery groups (801.9+/-537.7 vs. 724.3+/-542.4 pg/ml, respectively; P=0.572). The correlation of NT-proBNP with gestational age, birth weight, and cord blood pH was -0.616, -0.585, and -0.202, respectively. The mean values for NT-proBNP levels were compared according to the newborn gender (male vs. female; P=0.926), and Apgar score at 1 min [>6 (N=71) vs. <or=6 (N=13); P=0.001].
Conclusion: Vaginal delivery did not result in increased cord blood NT-proBNP levels reflecting cardiovascular stress to the fetal heart. NT-proBNP was inversely correlated with gestational age. Low Apgar score and umbilical cord blood pH appeared to induce the fetus to produce increased amounts of NT-proBNP.