Superior mesenteric artery blood flow velocity in small for gestational age infants of very low birth weight during the early neonatal period

In order to elucidate intestinal blood flow after birth in infants with int rauterine growth retardation, we measured superior mesenteric artery blood flow velocity in uncomplicated small for gestational age infants with a bir th weight of <1500 g by pulsed Doppler ultrasound in days 1 to 7 of life. p eak systolic blood flow velocity, time-averaged mean blood flow velocity an d end-diastolic blood flow velocity in the superior mesenteric artery signi ficantly increased with time. The resistance index and relative vascular re sistance in the superior mesenteric artery significantly decreased after bi rth. Compared with gestational age matched appropriate for gestational age infants and birth weight matched appropriate for gestational age ones, peak systolic blood flow velocity, time-averaged mean blood flow velocity and e nd-diastolic blood flow velocity in the superior mesenteric artery were low er in the small for gestational age infants. The difference between the sma ll for gestational age group and the gestational age matched appropriate fo r gestational age group was statistically significant. The resistance index and relative vascular resistance in the superior mesenteric artery tend to be higher in the small for gestational age group than in the appropriate f or gestational age groups. In conclusion, although intestinal blood flow ve locity in infants with intrauterine growth retardation increases after birt h, it is lower than appropriate for gestational age infants during the earl y neonatal period.