Prenatal diagnosis of disease.

We are still in the early days as far as antenatal diagnosis of fetal disease and abnormality are concerned. All of the techniques show a high degree of accuracy if used in the correct circumstances but, apart from the use of maternal blood to assess the Rhesus status and screen for neural tube defects and amniocentesis to search for age-dependent mongolism, present techniques are too cumbersome, inaccurate and dangerous to be offered as routine antenatal tests. The rapid development in ultrasound equipment and expertise and the recent advances in fetal blood sampling and biochemistry suggest that there will be continued and rapid expansion within the field.