Tetralogy of Fallot in the fetus in the current era

To compare the spectrum of tetralogy of Fallot detected recently in fetal life with that in previous reports of prenatal and postnatal experience.

All cases of tetralogy of Fallot, including those with pulmonary atresia, diagnosed between 1998 and 2005 inclusive were identified. Additional data for the 129 cases were collected, including associated congenital heart malformations, nuchal translucency measurement, karyotype and outcome.

The most common reason for referral was a suspicion of heart malformation at the routine obstetric ultrasonography scan and referrals increased during the study period. The mean gestational age at diagnosis was 20.6 weeks. The nuchal translucency measurement was above the 95th centile in 37 (47%) of the 78 fetuses in which it had been measured, and in 19/37 of the chromosomally normal fetuses. Of 112 fetuses with chromosomal analysis, 55 (49%) had anomalies, including 22q11 microdeletion in 15. There were additional extracardiac malformations in 65/129 cases (50%) and additional cardiac malformations in 73 (57%). In 70/129 (54%) cases, the parents chose termination of pregnancy. Overall survival to date in the continuing pregnancies is 77%.

Tetralogy of Fallot is increasingly recognized during routine fetal obstetric scanning. However, the spectrum of disease detected in the fetus remains biased towards those cases with extracardiac malformations and those with complex disease. As a result, even in the current era, the prognosis for the whole group of fetal cases under the diagnostic heading of tetralogy of Fallot continues to be much less favorable than would be expected of a postnatal series.