Congenital duodenal obstruction: early antenatal ultrasound diagnosis

Twenty-nine patients with congenital duodenaI obstruction (DO) detected as a "double bubble" (DB) on antenatal ultrasound (US) or diagnosed postnatally were seen at the Women's and Children's Hospital between 1985 and 1994; 24 (83%) had antenatal scans, with 21 (87%) DBs visualised. The 3 fetuses with normal scans who developed DO postnatally had duodenal "windsocks". Five of the 24 scanned patients (21%) were found to have a DB before 20 weeks' gestation: 1 simple duodenal atresia, 2 duodenaI atresias with chromosomal abnormalities (1 trisomy 21 and 1 triploidy), 1 biliary atresia with a pre-pyloric vein, and I malrotation. Sixteen (67%) cases were detected with scans after 20 weeks (range 28-36 weeks); 12 (75%) of these were done for polyhydramnios. In response to a questionnaire to 9 of the 16 parents whose fetuses underwent a late scan, 5 had had normal early scans elsewhere and 4 did not respond (4 of the remaining 7 had died and 3 were lost to follow-up). Eleven of the 29 patients (38%) had abnormal karyotypes, and 4 (22%) of the 18 with a normal karyotype had associated anomalies. Two sets of familial cases were noted. Early antenatal diagnosis of DO is possible in a minority of cases, and this early diagnosis may be associated with an increased risk of other pathology. Furthermore, early demonstration of a DB at routine US prior to 20 weeks allows appropriate counseling and the option of midtrimester termination, whereas this is more difficult later in the pregnancy. In all cases detected antenatally, planning of delivery and parent counseling should be achieved.