Fetal echocardiography in pregnancies of women with congenital heart disease - Clinical utility and limitations

Women with important cyanotic or uncyanotic, operated or unoperated congeni tal heart disease (CHD) have been shown to carry an inherent risk during pr egnancy for themselves and for their fetus. Obstetrical and fetal echocardi ography has recently been upgraded by new technical developments in ultraso und machines. These improvements have increased the detection rate of conge nital malformations and cardiac anomalies which ranged in the past between 4 and 60 56 for significant anomalies. Obesity or an unfavourable position of the fetus may, however, obscure the imaging quality and cause limitation s to visualise the fetal heart from different angles and thus prevent the d etection of anomalies. In addition, several cardiac anomalies develop throu ghout pregnancy and may not yet be present at an early date of screening. W hile the risk for a congenital cardiac malformation (CCM) in a normal popul ation is 0.8-1%, the recurrence rate for CCM increases to 2 to 3% when a pr evious child has been affected but will become significantly higher when ge netically determined anomalies have affected a family member or when the pr egnant woman (5.8%) has CHD. The aim of fetal screening in women with CCM i s to ascertain normal intrauterine growth, to exclude fetal CHD and/or to a scertain a malformation or arrhythmia which has been suspected during an ob stetrical screening. The acquired detailed echocardiographic knowledge of t he malformation or arrhythmia allows the explanation of a CCM to the future parents, to present therapeutic options during pregnancy or after birth an d to plan delivery in a tertiary center that provides early cardiovascular and/or catheter interventions and disposes of intensive care facilities for affected newborns. Under certain conditions, termination can be discussed in early pregnancy. Very recent publications have shown how important a pre natal diagnosis can become in a new-born with transposition of the great ar teries and a very restrictive foramen ovale (Circulation 1999). Therapeutic measures in the fetus have been attempted with very limited success so far ; successful life saving treatment does, however, exist for fetal arrhythmi as. In conclusion: Fetal echocardiography has become an important analytica l tool in high-risk pregnancies, especially when parents are affected by a CCM. The examination is safe and can be performed with a high predictive an d sensitivity rate.