Fetoscopic Documentation of Meconium Passage at 19 Weeks' Gestation

Abstract

A 19 + 1 weeks' primigravida underwent selective laser photocoagulation of communicating vessels for Quintero stage III twin-twin transfusion syndrome. No other fetal abnormalities were sonographically detected. During the procedure, the recipient twin passed greenish meconium through a patent anal sphincter (Figure A, Supplementary Video). Meconial particles floating in the amniotic fluid have been routinely observed by the authors during fetoscopic procedures performed as early as 16 weeks' gestation. The 2 fetal-placental blood circulations were successfully separated. It is estimated that 15% of births have meconium-stained amniotic fluid. The common concept correlating meconium-stained fluid with intrapartum asphyxia is currently under discussion because recent literature proposes that in utero defecation is in fact a physiologic phenomenon, which starts from the perforation of the anal membrane around 12 weeks' gestation and continues throughout the pregnancy. Recent accumulating observations point to the possibility that preterm intrauterine passage of meconium is not necessarily indicative of fetal distress, as traditionally assumed; however, twin-twin transfusion syndrome is a stressful condition for both fetuses. The presence of fetal bowel contents and digestive enzymes in the amniotic fluid is important for the prenatal diagnosis of fetal conditions such as anorectal atresia, biliary tract anomalies, and cystic fibrosis. The attached image and Supplementary Video point to the following 2 notions: 1The fetal anal sphincter is functional at 19 weeks of gestation.2As opposed to previous reports of white meconium by Ramon y Cajal et al,1Ramón y Cajal C.L. Martínez R.O. Defecation in utero: a physiologic fetal function.Am J Obstet Gynecol. 2003; 188: 153-156Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar, 2Ramón y Cajal C.L. Martínez R.O. In-utero defecation between weeks 14 and 22 of gestation: stools are whitish.Ultrasound Obstet Gynecol. 2004; 23: 94-95Crossref PubMed Scopus (8) Google Scholar, 3Ramón y Cajal C.L. Martínez R.O. Prenatal observation of fetal defecation using four-dimensional ultrasonography.Ultrasound Obstet Gynecol. 2005; 26: 794-795Crossref PubMed Scopus (9) Google Scholar the fetal meconium is green, which is evidence of fetal bowel enzymatic activity at that age of gestation. Fetal defecation has been experimentally induced in animal models and observed via ultrasound in human fetuses. This is a report of fetal meconium passage visualized endoscopically. Download .mpg (9.89 MB) Help with mpg files Supplementary Video