Prenatal hemodynamic disturbances -- pathophysiological background of intestinal motility disturbances in small for gestational age infants.

Uteroplacental insufficiency leads to fetal growth retardation which is a major cause of perinatal and postnatal morbidity. In the present study we investigated the relationship between prenatal hemodynamic disturbances and postnatal intestinal perfusion and gastrointestinal function in small for gestational age neonates. Prospectively, 124 preterm neonates with a birth weight below 1500 g were assigned to one of two groups according to the prenatal Doppler sonographic measurements: neonates with or without prenatal hemodynamic disturbances. We defined a pathological fetal perfusion using a pulsatility index of uterine arteries, umbilical artery and fetal thoracic aorta above the 90th percentile and a pulsatility index of the middle cerebral artery below the 10th percentile of a normal group. We compared intestinal adaptation in both groups as well as the blood flow velocity wave forms of the superior mesenteric artery in all neonates. Postnatally, all 42 neonates with prenatal hemodynamic disturbances were classified to be small for gestational age. Thirty-seven of these neonates developed abdominal problems with delayed meconium passage, abdominal distension, bilious vomiting and a delay in tolerating enteral feeding within the first days of life. Five of them needed surgical intervention, but none of these infants revealed typical signs of necrotizing enterocolitis. In contrast, all neonates born after normal prenatal perfusion were classified as appropriate for gestational age. Only 19 of 82 neonates of this group showed signs of intestinal disturbances postnatally. Doppler sonography demonstrated significantly lower systolic, mean and END-diastolic flow velocities, and higher pulsatility indices of the superior mesenteric artery in neonates with prenatal hemodynamic disturbances. This may occur as a result of a postnatally persistent redistribution of regional blood flow and results in gastrointestinal problems and may adversely affect gut motility.