In utero supplemental fetal feeding in an animal model: effects on fetal growth and development.

That the fetus swallows amniotic fluid and has the capability of intestinal absorption of protein and carbohydrate is known, but its significance in fetal nutrition is not clear. We have infused nutrient solutions of dextrose and amino acids intra-amniotically in a chronic third-trimester fetal rabbit model and examined the effects on fetal growth and development. Over a 5-day period, 26 fetal rabbits received graded doses of dextrose in water with or without amino acids infused continuously into the amniotic space. At the time of delivery, fetal body, liver, and brain weight, crown-rump length, and brain protein content were significantly higher in the infused rabbits than in noninfused controls. Amniotic fluid, serum, and gastric content glucose levels were significantly higher in infused fetuses. There was a linear relationship between nonprotein calories administered and fetal growth within the infused group. No toxicity of infusates in the fetus was noted, although technical complications relating to the infusion apparatus were common. We conclude that third-trimester intra-amniotic infusion of nutrient solutions enhances fetal growth in this rabbit model. We speculate that this technique may be of value in the antenatal treatment of growth-retarded fetuses.