The effects of intraamniotic human neonatal urine and meconium on the intestines of the chick embryo with gastroschisis

Background/Purpose: Urinary waste products in the amniotic fluid has been i mplicated as a cause of intestinal damage (ID) in gastroschisis based on th e fact that fetus urinates physiologically into the amniotic cavity. Howeve r, experimental and clinical data suggest that intrauterine defecation is a physiological event, thus gastrointestinal waste products also may be resp onsible for ID in gastroschisis. An experimental study was performed to inv estigate the effects of intraamniotic human neonatal urine and diluted meco nium on the intestines of chick embryo with gastroschisis. Methods: Five-day-old fertilized chick eggs (Gallus domesticus) were used. Gastroschisis was created through amniotic cavity without opening the allan toic cavity. Sterile urine and meconium were obtained from newborn humans, and 1% meconium suspension was prepared. The eggs were divided in to 3 grou ps. In the first group, gastroschisis was created, and amniotic fluid was r einstilled without changing its composition (control group). Equal amounts of amniotic fluid and urine mixture was instilled into the amniotic cavity in second group (urine group) and 1% meconium suspension was instilled in s imilar fashion in the third group after creation of gastroschisis (meconium group). Results: Histopathologic features of the intestines of the urine group did not differ from the intestines of the control group. The meconium group's b owel showed serosal thickening, inflammation, focal fibrin, and collagen de posits. Histopathologic changes of intestines induced by intraamniotic dilu ted meconium are consistent with the ones described for human gastroschisis specimens. Conclusion: Gastrointestinal waste products seem responsible for the ID in gastroschisis rather than urinary waste products. Copyright (C) 2000 by W.B . Saunders Company.