While the procedure for removal of amniotic fluid has minimal risk for the fetus and mother, there are slight risks of bleeding, leakage of fluid, or infection. There also is a remote chance of miscarriage. When being performed for prenatal diagnosis, amniocentesis is usually offered to women 35 years or older, women with a child with a chromosomal abnormality, parents with a child with neural tube defect, and women with elevated serum alpha-fetoprotein, or when one parent has a chromosomal abnormality or is a carrier for a metabolic disease. Parents who agree to amniocentesis must be prepared to make a decision whether or not to abort the fetus if the laboratory tests indicate the presence of a birth defect. Frequently, however, parents who have a high risk for having an abnormal child find that the developing fetus is normal and the prognosis for delivery of a healthy baby is excellent.
Local anesthesia is used to minimize discomfort.
The patient is cautioned not to move during the procedure lest the needle become displaced. A syringe is attached and fluid is withdrawn. It is sometimes necessary to repeat the procedure because of an insufficient sample or unsuccessful laboratory testing. The repeat procedure is done several days after the first. Following amniocentesis the patient is observed for changes in blood pressure, excessive leakage of fluid, and signs of infection.