Antenatal diagnosis of fetal abnormalities.

Fetal abnormalities may be strongly inherited e.g. in the Mendelian diseases. Some of the abnormalities are due to detectable chromosome anomalies, while the majority of fetal abnormalities arise as a result of the interaction of polygenes and environmental factors. The process of fetal abnormality diagnosis depends on a careful taking of the history and its evaluation. The clinical examination of the fetus by real time ultrasound, if relevant and finally special investigations which are to some extent invasive such as chorionic villus sampling, amniocentesis and fetal blood sampling. The fetal tissue so obtained may be assessed for their genetic structure by DNA recombinant methods, or the disease may be diagnosed by analysis of the genic products. The commoner hereditary diseases probing fetal abnormalities in S.E. Asia are described and the diagnosis of these diseases discussed. Fetal diagnosis, at the moment, is still labour intensive and costly and must be applied in a discriminate fashion.