Antenatal ultrasonographic diagnosis of trisomy 18 (Edwards syndrome)

Current status of prenatal diagnosis, operative management and outcome of esophageal atresia/tracheo-esophageal fistula

Ultrasonographic features suggestive of esophageal atresia with or without tracheo-esophageal fistula (EA/TEF) are only in a small minority of fetuses with EA/TEF (<10%) identifiable on prenatal scans.The prenatal diagnosis of EA/TEF relies in principle, on two nonspecific signs: polyhydramnios and absent or small stomach bubble. Polyhydramnios is associated with a wide range of fetal abnormalities, but most commonly it pursues a benign course. Similarly the sonographic absence of a stomach bubble may point to a variety of fetal anomalies.The combination of polyhydramnios and absent stomach bubble in two small series offers a modest positive predictive value of 44 and 56% respectively. Prenatal scanning for EA/TEF identifies a larger proportion of fetuses with Edwards syndrome; there is also a higher proportion of isolated EA in comparison to postnatal studies.Current ultrasound technology does not allow for a definite diagnosis of EA/TEF and therefore, counseling of parents should be guarded.Postnatal diagnosis of EA is confirmed by the failure to pass a firm nasogastric tube into the stomach; on chest X-ray, the tube is seen curling in the upper esophageal pouch. Corrective surgery for EA/TEF is well established and survival rates of over 90% can be expected.

Acute and subacute polyhydramnios in singleton pregnancies

Over a 10-year period when 51,022 singleton infants were delivered, 19 pregnancies (1 in 2,685) were complicated by acute polyhydramnios 17 (1 in 3,000) by subacute polyhydramnios and 501 (1 in 102) by chronic polyhydramnios. The incidence of major congenital malformations in singleton pregnancies associated with acute polyhydramnios was 63% and the perinatal mortality rate was 74%. When subacute polyhydramnios occurred in singleton pregnancies, the incidence of major congenital malformations was 65%, similar to acute polyhydramnios, but the perinatal mortality rate was only 35%. The comparable figures for chronic polyhydramnios in singleton pregnancies were a major malformation incidence of 14% and perinatal mortality rate of 10%. The type of onset of polyhydramnios, acute, subacute or chronic is therefore the most important indicator of prognosis. In patients with gross polyhydramnios, acute renal failure must be specifically excluded.