Clinic experience of prenatal diagnosis of cystic fibrosis by use of linked DNA probes.

96 families at risk of having a child with cystic fibrosis have been counselled about prenatal diagnosis by the use of linked DNA probes. Of the first 30 pregnancies 9 children have been born and confirmed to be free from CF, as predicted; 8 pregnancies were terminated (1 of these was found to be miscarrying at time of termination); 12 pregnancies, in which the fetuses are predicted to be unaffected, are in progress; and 1 has miscarried. No couple with a prenatal prediction of CF decided to continue with the pregnancy. 1 pregnancy was terminated because of a 50:50 chance of an affected fetus. In 1 twin pregnancy the affected fetus was selectively aborted, and the other baby was confirmed after birth to be unaffected, as predicted. In the other twin pregnancy the two chorionic plates could not be samples separately; the pregnancy was continued on the basis of normal findings for the lower plate, and both twins have turned out to be normal. Many couples at risk see early prenatal diagnosis as a way to help them have an unaffected child.