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A woman was referred at 25 weeks' gestation with decreased fetal movements. Ultrasound revealed a large solid fetal abdominal mass and gross fetal ascites. Amniocentesis and viral titers were normal. On subsequent ultrasound examinations, the mass and ascites slowly disappeared, but a small bowel obstruction developed. Spontaneous labor occurred at 35 weeks and the child was born with a distended abdomen. At laparotomy there was type 3 jejunal atresia, indicating that the fetal mass and ascites were secondary to this antenatal small bowel ischemia.

The common clinical practice of intravenous feeding of the pregnant woman poses the question of the effect on the fetus of such infusions. We have used the sheep as a model to study the change in fetal amino acid levels after a maternal infusion of Synthamin 13. The maternal plasma aminogram largely reflects the amino acid pattern in the infusate. However, in the fetal circulation only the branched chain amino acids (leucine, isoleucine and valine), phenylalanine and alanine rose significantly after infusion. Only leucine and isoleucine were observed to spill into the fetal urine. The results suggest that the ovine placenta selectively modifies the amino acid profile presented to the fetus when the maternal plasma aminogram is distorted. However, the fetus is not totally protected from changes in phenylalanine, which in high concentrations, is detrimental to normal development.

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