The most reliable method of diagnosis is to examine a sample of fluid from the amniotic sac, sometime between the fifteenth and eighteenth week of pregnancy. The sample is obtained by amniocentesis. Microscopic examination of the cells in the fluid then reveals possible abnormalities in the chromosomes. Congenital anomalies that can be diagnosed in this way include Down's syndrome, spina bifida, and anencephaly. Sometimes, the diagnostic use of ultrasound can detect abnormalities of the skull or spine.
Treatment depends entirely on the nature and severity of the condition.
Many anomalies can be treated, but for some there is no treatment. Abortion might be considered if serious fetal disorders are found early in a pregnancy. The decision to abort rests with the parents and is made after considering the advice of the physician and specialists on the nature of the disorder and the consequences of abortion. Statistics disprove this commonly held belief. Genetic counseling deals with such questions.