Very early postnatal changes in splanchnic circulation in term infants

Reversed blood flow has been reported in the superior mesenteric artery (SMA) in 92% of healthy term newborns at 2 h of age. By 24 h after birth the end-diastolic velocity became positive in all of the infants.

To characterize hemodynamic changes in the coeliac artery and superior mesenteric artery in healthy term newborns during the first 6 h after birth and to specify the time interval when the negative values of end-diastolic velocity in the superior mesenteric artery become positive.

Our study included 30 healthy term newborns. The blood flow velocity was assessed by Doppler ultrasonography at 2 h, 4 h and 6 h after birth.

The end-diastolic velocity in the superior mesenteric artery changed from negative values at the age of 2 h (-0.9 cm/s, range -13.2 to 0.0) to positive (7.08 cm/s, range 6.3 to 13.5, P < 0.001) at 6 h after birth. In the coeliac artery, the end-diastolic velocity increased during this period, but negative values were not observed (11.8 cm/s, range 9.3 to 13.9 at 2 h and 18.03 cm/s, range 14.2 to 27.6 at 6 h).

Important changes occur in splanchnic circulation during the first 6 h after birth. The rise in end-diastolic velocity in the superior mesenteric artery from negative to positive values in 83% of healthy term newborns is the most important change.