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 postnatall y were seen at the Women's and Children's Hospital between 1985 and 1994; 2 4 (83%) had antenatal scans, with 21 (87%) DBs visualised. The 3 fetuses wi th 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 sca ns after 20 weeks (range 28-36 weeks); 12 (75%) of these were done for poly hydramnios. In response to a questionnaire to 9 of the 16 parents whose fet uses underwent a late scan, 5 had had normal early scans elsewhere and 4 di d 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 th e 18 with a normal karyotype had associated anomalies. Two sets of familial cases were noted. Early antenatal diagnosis of DO is possible in a minorit y of cases, and this early diagnosis may be associated with an increased ri sk of other pathology. Furthermore, early demonstration of a DB at routine US prior to 20 weeks allows appropriate counseling and the option of midtri mester termination, whereas this is more difficult later in the pregnancy. In all cases detected antenatally, planning of delivery and parent counseli ng should be achieved.