The influence of mode of delivery on the level of catecholamines in umbilical cord blood of neonates

Abstract

To determine whether mode of delivery is associated with the level of catecholamines in umbilical cord blood of neonates. A study was carried out on 150 neonates. Among them 90 were healthy while 60 were diagnosed fetal distress. Then the subjects were first divided into 5 groups according to different modes of delivery: 30 were delivered by spontaneous labor for vaginal delivery without any pain relief; 30 by vaginal delivery with epidural anaesthesia; 30 by caesarean section without labor; 30 by vaginal delivery with low forceps because of fetal distress and 30 by caesarean section of emergency because of fetal distress. After delivery, umbilical cord blood of both artery and vein was collected for determination of norepinephrine (NE), epinephrine (E), and dopamine (DA). (1) The concentration of NE and E of umbilical artery were different in each group (P < 0.01), the group with the highest concentrations of NE and E was the ones delivered by vaginal delivery with low forceps [(73 +/- 6) ng/L, (37.8 +/- 1.8) ng/L] while caesarean section [(35 +/- 5) ng/L, (27.2 +/- 1.2) ng/L] was associated with significantly lower concentrations of NE and E of umbilical artery. The ones delivered by vaginal delivery with low forceps [(33.7 +/- 4.5) ng/L] and caesarean section of emergency [(32.9 +/- 4.5) ng/L] had higher concentrations of DA compared with any other group (P < 0.01). (2) The concentration of NE and E of umbilical vein were different in each group (P < 0.01) just like that of umbilical artery. The ones delivered by vaginal delivery with low forceps and caesarean section of emergency had higher concentrations of DA compared with any other group (P < 0.01). (3) The neonates with fetal distress had higher levels of catecholamine both in umbilical artery and umbilical vein than the healthy ones (P < 0.01); at the same time, the ones with fetal distress got lower Apgar scores 1, 5, 10 min after born contrasted to the healthy ones. If no indication for caesarean section exists, delivery by vaginal naturally can give higher level of catecholamines in cord blood, thus the neonate can get ready to adapt to the new environment better.