Prenatal ultrasound diagnosis of gastrointestinal malformations.

Prenatal ultrasonography is commonly used to detect fetal structural abnormalities. The aim of this study was to evaluate the reliability of fetal sonography in the detection of congenital gastrointestinal malformations (GIM). From a prospective database of all major structural fetal anomalies detected by ultrasound over 3 years in a region with a population of 3.5 million and an annual birth rate of 52,000, 294 reports of GIM were identified and reviewed. There were 220 confirmed cases of GIM, of which only 35 (16%) had been correctly identified prenatally. Of 84 prenatal diagnoses of GIM, only 35 (42%) were confirmed postnatally. Prenatal ultrasound was most reliable in the detection of duodenal obstruction (55% confirmed cases identified prenatally) and least reliable in malformations of the hindgut. Of 44 cases of nonspecific sonographic bowel abnormality (eg, echogenic bowel) with adequate follow-up, only 12 (27%) had a confirmed GIM after delivery. This study demonstrates that the prenatal ultrasound scan is still unreliable in the detection or exclusion of fetal GIM, and consequently clinicians involved in prenatal sonography or counselling should exercise caution in making such diagnoses.

Cystic hygroma: comparison between prenatal and postnatal diagnosis.

Antenatal diagnosis of congenital malformation often leads to opportunities for intervention in the pregnancy that may have a profound effect on the outcome of the fetus. The accuracy of the diagnostic technique is a critical factor in judging the appropriateness of such interventions. This article reports the current accuracy of prenatal ultrasound diagnosis of cystic hygroma (CH) in a region with a population of 3.5 million and an annual birth rate of 52,000. During a 32-month period (to December 1994), 113 diagnoses of CH were reported to the South East Thames Regional Congenital Malformation Registry. Eighty-nine diagnoses were made prenatally and 24 were made postnatally (at delivery or postmortem). The number of confirmed cases of CH was 52 (46% total diagnoses). The prenatal diagnoses were established at a mean gestational age of 19 weeks. Fifty-six (63%) pregnancies with a prenatal diagnosis of fetal CH were terminated; in only 25% of these was the presence of CH confirmed after termination. Overall, of the 89 prenatal diagnoses, 28 (32%) were confirmed, 45 (50%) were incorrect, and 16 (18%) could not be confirmed or refuted. Only 24% of fetuses with a prenatal diagnosis of CH were live born. The survival rate at 1 year for the live-born infants with CH in this series was 88%. The diagnosis of fetal CH has a recognised association with chromosomal abnormalities, and consequently may lead to termination of the pregnancy. A potential error rate of almost 70% in the prenatal ultrasound diagnosis of this condition requires clinicians to adopt a more cautious approach to the management of the fetus with "cystic hygroma."

Impact of antenatal diagnosis on incidence and prognosis in abdominal wall defects.

The authors review data from the Congenital Malformation Registry in South East Thames regarding fetal abdominal wall defects. Over 24 months, 80 cases were observed (40 gastroschisis, 40 exomphalos). Live-born infants with gastroschisis had few associated anomalies and an excellent prognosis (83% survival rate). Exomphalos is associated with an increased rate of life-threatening anomalies and chromosomal defects. The latter cases often are terminated prenatally. If these cases are excluded, the 1-year survival rate for liveborn infants with exomphalos is favorable (close to 80%). Fetuses in whom gastroschisis and exomphalos are identified by ultrasonography but who have no associated life-threatening chromosomal anomalies should have a favorable prognosis.