Intestinal dilatation in the fetus.

Correspondence to: Mr SJ K Holmes. Introduction There are now sufficient data on the sonographic appearance ofnormal fetal gut to allow intestinal abnormality in the antenatal period to be diagnosed, although as yet relatively little attention has been paid to the implications for the child. We present eight such cases. Six children were found to have midgut atresia, three of whom had evidence of antenatal perforation. Two of the six had intestinal malrotation, which we believe, was responsible for the atresia and two had meconium ileus not associated with cystic fibrosis. One child was found to have intestinal pseudo-obstruction and one a high anorectal malformation. Intestinal dilatation in the otherwise well newborn child is usually due to obstruction. The differential diagnosis includes mid and hindgut atresia, meconium ileus, Hirschsprung's disease and midgut volvulus. Although the first two conditions soon declare their presence, Hirschsprung's disease and the intestinal malrotation that leads to volvulus may not be apparent at birth. Structural abnormalities in the fetus are revealed in considerable detail by ultrasonography. The appearances of anomalies in the neural tube, abdominal wall, and renal tract are relatively well established, but description of the pathology affecting the fetal bowel is still far from complete. The first report of bowel dilatation in the fetus was by Lee and Warren in 1977. They found multiple dilated tubular structures on ultrasound scan at 35 weeks' gestation.1 Jejunal atresia was found during surgery in the early neonatal period. Subsequent reports confirmed that fetal intestinal obstruction can be detected by ultrasound scanning in the antenatal period. The pathology included midgut or hindgut atresia, meconium ileus, malrotation and Hirschsprung's disease. Meconium cyst and peritonitis following perforation have also been described. Eight such instances were noted at St George's Hospital, London, between 1987 and 1994. Each had an ultrasonic diagnosis of intestinal dilatation in the antenatal period with intestinal pathology confirmed after the child was born. Six children had midgut atresia, three of whom had evidence of antenatal perforation. Two of these had intestinal malrotation which we believe was responsible for the atresia. Two had meconium ileus, but no evidence of cystic fibrosis. One child was found to have intestinal pseudo-obstruction and one an anorectal malformation. A ninth child was observed to have an intrauterine volvulus, leading to ileal atresia, but dilated bowel was not reported antenatally. The sonographic appearances