Amniocentesis

This fluid contains cells shed by the fetus. The cells contain genetic information that can be tested for chromosomal disorders and open neural tube defects. Your doctor may recommend amniocentesis for any of the following reasons:

• Family history or previous child with a genetic disease or chromosomal or metabolic disorder
• Abnormal findings on prenatal ultrasound
• Risk of open neural tube defects like spina bifida or myelomeningocele
• Maternal age over 35 by the pregnancy due date
• Abnormal maternal screening test results

Complications from amniocentesis are rare, but do occur. There is a one in 300 or less risk of losing your pregnancy from the procedure, primarily due to the chance of rupturing membrane. Later in pregnancy, ruptured membranes can lead to preterm birth. There is also a small risk of infection inside the uterus.

Amniocentesis testing usually occurs during the second trimester, but can also be done in the third trimester. Before having an amniocentesis procedure, let your doctor know if you have a history of bleeding disorders or if you are taking blood-thinning medicine, as these may affect the procedure.

In rare cases, amniocentesis can cause some of the baby’s blood cells to enter the mother’s bloodstream. Let your doctor know if you are Rh negative. If this is the case and your baby is Rh positive, your body’s immune system may produce antibodies against your baby’s blood.