Nutritional role of amniotic fluid: clues from infants with congenital obstruction of the digestive tract.

AIMS: To investigate the role played by amniotic fluid in late fetal nutrition by analysis of infants born with digestive tract atresia.

METHODS

Birth weight (BW), gestational age and gender of infants born with oesophageal (OA), duodenal (DA), jejunal (JA) and ileal atresia (IA) were recorded and BW Z-scores compared. Infants with incomplete obstruction (stenosis), chromosomal or syndromic conditions and multiple congenital malformations were excluded. Term infants admitted with suspected postnatal intestinal obstruction in whom no congenital malformation was found were used as a control group.

RESULTS

A total of 584 infants were identified comprising 148 OA, 60 DA, 26 JA and 57 IA with 293 in the control group. Infants with OA and DA had statistically significantly lower BW Z-score than controls. However, BW Z-score for infants with more distal atresia (JA and IA) was similar to controls. When compared with infants with OA, BW Z-score for infants with more distal atresia was higher than that for OA. BW Z-score in infants with OA was significantly lower in those born at term compared with those born preterm (mean±SD -0.92±1.0 vs -0.48±0.87; p=0.01) with a significant negative correlation between BW Z-score and increasing gestational age (R2=0.12; p<0.0001). This effect of gestational age was not seen in other atresias.

CONCLUSION

These observations support the concept that reduced enteral absorption of amniotic fluid due to high digestive tract obstruction in utero reduces fetal growth. The effect is greater when the obstruction is more proximal and with advancing gestation.