Mode of delivery and perinatal cerebral blood flow

OBJECTIVE: To ascertain whether the perinatal cerebral blood flow velocity differed between vaginally delivered appropriate for gestational age (vag. AGA) term babies, AGA babies delivered by Caesarean section (C.s. AGA), and small for gestational age (C.s. SGA) babies also delivered by Caesarean section. STUDY DESIGN: Forty-five babies were examined by Doppler ultrasound of the middle cerebral artery prior to and immediately after delivery, and at 1 h and 24 h after birth. The pulsatility index (PI) and time-averaged maximum velocity (TAMXV) were calculated. RESULTS: No differences in TAMXV were found between the vag. AGA and C.s. AGA groups at any of the four recordings. A significantly higher PI value was found in the C.s. AGA group 1 h after birth. The C.s. SGA group had lower PI values before and just after birth, but did not differ significantly from the C.s. AGA group at 1 h or 24 h after birth. CONCLUSIONS: The results suggest mode of delivery to have a transitory effect on cerebral vascular resistance in healthy term AGA babies. The C.s. SGA group differed in the initial recording just after birth, but later manifested similar blood flow velocities in middle cerebral artery as the C.s. AGA group.