The role of amniotic fluid in influencing neonatal birth weight.

OBJECTIVE

We studied 123 neonates with atresias of the gastrointestinal tract at different levels to assess the role of amniotic fluid in the growth and development of the gastrointestinal tract. Our hypothesis was that significant differences in birth weight between groups otherwise comparable would suggest an intrauterine nutritive role for amniotic fluid. Our second hypothesis was that there is a trophic role of amniotic fluid on intestinal epithelium affecting its functional maturity. Establishing earlier tolerance of enteral nutrition in neonates with distal as compared with proximal atresias would support this hypothesis.

STUDY DESIGN

Overall, 123 neonates from a single institution, with duodenal atresia (DA), jejuno-ileal (JIA) and colonic atresia (CA), were separated into three groups. Birth weight, gestational age, associated anomalies and duration of total parenteral nutrition intake were recorded. Neonates with multiple atresias and gastroschisis were excluded from analysis. Statistical analysis of differences between groups was carried out using analysis of variance (ANOVA) for independent samples. Post-ANOVA pairwise comparisons were carried out using the Tukey-HSD test.

RESULT

Fifty-four DAs, 62 JIAs and seven CAs were included. The mean birth weight, 2380.5 g (s.d. 988) in DA, 2814 g (s.d. 755) in JIA and 3153 g (s.d. 527) in CA were significantly different between groups (P=0.011). The Tukey-HSD test showed that DA<JIA<CA was also significant (P<0.01). The mean gestational age (Tukey-HSD test, P=not significant (NS)) and presence of associated anomalies (Wilcoxson, P=0.08) did not differ significantly among the groups. Total parenteral nutrition was stopped at a mean period of 18 days in DA, 15.6 days in JIA and 15.6 days in CA (Tukey-HSD, P=NS).

CONCLUSION

Proximal atresias have a significantly lower birth weight than atresias distal in the gastrointestinal tract. This cannot be explained on the basis of gestational age or associated anomalies. Although not conclusive, this study implies an intrauterine nutritive role for amniotic fluid. Further studies are needed to prove the trophic effects of amniotic fluid on the gut.