Chorionic villus biopsy is a procedure used to culture cells from the chorionic membrane, a membrane that is part of the fetus and surrounds the amnio...
Medical professionals can use several special screening techniques to detect abnormalities while a fetus is still developing in the uterus. One such method is ultrasound, a scanning and imaging technique that provides a picture of the fetus. A second screening technique, amniocentesis, is usually only performed when doctors believe there may be fetal health risks. During this procedure, a small amount of amniotic fluid is removed from the amniotic sac. The fluid is drawn into a hypodermic needle that has been inserted through the mother’s abdominal wall. Amniotic fluid contains cells shed by the fetus. These cells carry the fetal genetic code and can be cultured and examined for genetic abnormalities. For example, Down syndrome can be diagnosed by examining cultured cells from the fetus. An examination of the amniotic fluid itself can also provide important information about the fetus. There are certain proteins that, when detected in very high amounts, indicate neural defects. Spina bifida is one condition that can be diagnosed by examining amniotic fluid. Amniocentesis is usually performed only after the sixteenth week of pregnancy. Before this time, there are not enough fetal cells or amniotic fluid to examine. Because the cell culture can take several weeks, the mother may not know the results of her testing until late in her pregnancy. There are several new techniques that may replace amniocentesis. Chorionic villus biopsy is a procedure used to culture cells from the chorionic membrane, a membrane that is part of the fetus and surrounds the amniotic sac. Both amniocentesis and chorionic villus biopsy involve taking samples from the uterus and present risks to the fetus. A new experimental technique involves separating fetal cells from the mother’s blood. The fetal cells are examined just as in amniocentesis, but this technique presents no risks to the fetus because the sample is taken from the mother’s blood rather than from her uterus.
