Genetic counselling: a tool for the prevention of some abnormal pregnancies.

A pregnancy contains a fetus, and if the fetus is abnormal the pregnancy is in one sense also abnormal. In this context, a consideration of genetic counselling is apposite to the pathology of pregnancy. Although counselling is not in itself a pathologist's technique, it is becoming increasingly reliant on sophisticated laboratory services, and genetic counsellors are often members of laboratory-based teams. Genetic counselling has been defined as 'a communication process which deals with the human problems associated with the occurrence, or risk of recurrence, of a genetic disorder in a family . . .' (American Society of Human Genetics, 1975). The accent is on communication, leading to an appreciation by the patient or his family of the nature and prognosis of the disorder, and the likelihood that it will recur in the family. Counselling is only one aspect of the newly emerged discipline of medical genetics, a subspeciality dealing with diagnosis, laboratory investigation, prognostication and treatment of genetically determined disorders. This paper will briefly review the subject of genetic counselling, considering (a) the types of medical conditions for which referral to a medical geneticist is appropriate, (b) the size of the population suffering from genetically determined disorders, (c) the techniques, and (d) the efficacy of genetic counselling.