The outcome of Down syndrome fetuses presenting with sonographic abnormalities in the second or third trimester is unclear. Therefore, we studied 55 pregnancies referred because of sonographically suspected fetal structural anomalies or growth retardation due to trisomy 21. A detailed ultrasound scan was performed in all cases to delineate the structural anomalies. Congenital heart malformations (CHMs) were diagnosed pre- and postnatally in 29 out of 55 Down fetuses (53%), with complete or incomplete atrioventricular septal defects (AVSDs) and ventricular septal defects (VSDs) being the most frequent anomalies. The most frequent noncardiac findings were a short femur (45%) and a small-for-gestational age (SGA) fetus (27%). Termination of pregnancy was carried out in 25 out of 55 pregnancies (45%). Of the 30 continued pregnancies, 10 ended with intrauterine death. The remaining 20 pregnancies resulted in the delivery of a live-born infant whose prognosis was poor, with a 1-year survival of only 60%. Combining intrauterine death and death in the first year indicated that the overall survival rate was only 40%. Fatal outcome was noted in 68% (13/19) in the presence of CHM, in 83% (10/12) in SGA fetuses, in 86% (6/7) in combined CHM and SGA, but only in 17% (1/6) in the absence of CHM and SGA. This study indictes that second- and third-trimester in utero diagnosis of Down syndrome has a poor outcome when associated with CHM and/or SGA. This is important in the genetic counseling of the parents.
Copyright 2002 Wiley-Liss, Inc.