More than fetal urine: enteral uptake of amniotic fluid as a major predictor for fetal growth during late gestation

The purpose of our study was to investigate the importance of amniotic fluid (AF) for fetal growth during late gestation using esophageal atresia (EA) patients as a model. In this retrospective cohort study, we compared the z-scores adapted for birth weights (BW z-scores) for each of 517 European newborns with congenital pre-gastric intestinal atresia, i.e., EA, to a European reference population. To account for the influence of the intestinal atresia on fetal growth per se, we compared adapted birth weights for each of 504 European newborns with post colonic intestinal atresia (anorectal malformation (ARM) with atresia of the anus) to the same European reference population. Analysis of the complete cohort showed (i) a significantly higher rate of small for gestational age newborns among EA compared to ARM newborns (p < 0.001) and (ii) significantly lower BW z-scores among EA compared to ARM newborns (p < 0.001). BW z-scores of EA newborns were significantly lower in term compared to preterm newborns with an inverse correlation with gestational age (GA) (Spearman correlation coefficient, r = -0.185, p < 0.001). Conclusions: Enteral uptake of AF seems to play a pivotal role in fetal growth during late gestation.