Nonobstructive dilatation of the fetal bowel in twin gestations. A possible sonographic marker for fetal compromise

OBJECTIVE: To assess the possible association of in-utero bowel dilatation and circulatory changes with fetal compromise. METHODS: A retrospective survey of all ultrasound examinations was performed at the Chaim Sheba Medical Center (n approximately 10,000) between 1995 and 1999. Cases with ultrasonographic evidence of bowel dilatation, but without evidence of obstruction, were recruited. In utero Doppler studies of umbilical, splenic, superior mesenteric arteries, and middle cerebral artery (MCA) were performed: systolic/diastolic ratio (S/D), pulsatility index (PI) and resistance index (RI) were calculated in the above arteries and compared with those of normal fetuses. Nonstress test and cord blood pH were also assessed. Neonatal medical records were procured. RESULTS: Four fetuses, all of who were products of twin gestations, showed bowel dilatation without evidence for obstruction. Three of the four fetuses were small-for-gestation-age (SGA) and of bichorionic gestation, while one was of monochorionic twin gestation, with twin transfusion syndrome. In all three SGA fetuses, Doppler studies revealed increased peripheral resistance in the umbilical artery and adaptive peripheral vasodilatation in the fetal midcerebral, splenic and superior mesenteric arteries. In all cases, an abnormal nonstress test led to prompt delivery. CONCLUSIONS: Acute fetal bowel dilatation in a twin gestation is associated with abnormal splanchnic and gut perfusion that may lead to fetal compromise.