Haemodynamic changes in the brain after vaginal delivery and caesarean section in healthy term infants

Abstract

Objective To investigate whether the mode of delivery may affect neonatal cerebral haemodynamics during the first hour of life. Design Prospective study.Sample Healthy infants with gestational age ! 37 weeks and birthweight appropriate for gestational age, born after uncomplicated pregnancy by vaginal delivery or elective caesarean section, two to five hours after the delivery. Methods Near infra-red spectroscopy was used to measure changes of oxygenated haemoglobin, deoxygenated haemoglobin, oxidized-reduced cytochrome aa3, and mean cerebral oxygen saturation (mixed cerebral oxygen saturation ¼ oxygenated haemoglobin/total haemoglobin). Changes in cerebral blood volume were calculated. Results Near infra-red spectroscopy data did not show significant differences between infants born by vaginal delivery or by caesarean section. There was a significant decrease of oxygenated haemoglobin and change of cerebral blood volume values at 120 and 180 minutes in both the groups, while deoxygenated haemoglobin and oxidized-reduced cytochrome aa3 were unchanged. Conclusions A decrease of cerebral blood volume occurs after birth and this occurs both in infants born by vaginal delivery and by caesarean section.

Assessment of fetal cerebral arterial and venous blood flow before and after vaginal delivery or Cesarean section

“…Hypoxemia is also a strong vasodilator, while an increase in oxygen tension correlates with decreased cerebral blood flow velocities20, 21. However, in a more recent study it was reported that arterial oxygen saturation and carbon dioxide tension did not change significantly in newborns16. The increase in cerebral blood flow velocity at 24 h after birth depends on multiple factors and is not completely clear; the increase in arterial blood pressure, ductal closure and increase in cerebral metabolism probably play an important role11.…”

“…Indeed, the blood flow available to the infant for organ perfusion in early neonatal life is equal to left ventricular output, minus the volume of left‐to‐right ductal shunting15. The left‐to‐right shunt through the ductus arteriosus, which progressively increases in the first hours of life contemporaneously with the physiological drop in pulmonary vascular resistance, could favor the progressive lowering of cerebral perfusion16. In fact, it has been shown that in cases of patent ductus arteriosus, cerebral diastolic blood flow velocities decrease and the resistance index increases in newborn infants17.…”