Amniocentesis is a diagnostic procedure undergone during pregnancy. It is most commonly used to check the baby’s chromosomes. Amniocentesis is performed occasionally to test for other disorders in pregnancy such as infection or genetic disorder. The tests look for substances in the fluid itself, rather than at the baby’s chromosomes. We do not usually need a local anesthetic. Before the procedure, the gel is applied over the abdomen. The person is scanned to check the positions of both the baby and the placenta (afterbirth).
The amniocentesis is performed to find out:
- If the karyotype (the chromosomes) of the baby is (are) normal
- If there is evidence of a neural tube defect (spina bifida or open spine)
- If there is evidence that the baby might have had an infection
- If the lungs of the baby are ready to breathe
How is the amniocentesis performed?
The amniocentesis is performed under ultrasound guidance. We would first look at the baby to make sure that there is no condition that would interfere with the procedure. Then, we would select an area that we feel appropriate to put the needle. We try to avoid going through the placenta as we try to stay away from the baby. We would disinfect the skin, and make sure that the baby is still in the correct place. We would then insert the needle and connect it to a plastic tubing to prevent the motion from being transmitted to the baby. Then we would insert the needle going through your skin and through the muscle of the uterus. Once done, we would take about 20-30cc (2/3 to 1 oz) of fluid. The baby would make up this fluid in about 4-6 hours. We would then remove the needle and visually display the baby’s heart again. The samples would then be sent to the lab, and you would have to sign that you consent to have the sample tested.
Care after the amniocentesis
Complications of the amniocentesis are rare, but in order to be on the safe side, we would like you to have a relaxed end of the day. This means no lifting kids or groceries, no aerobic classes, no jogging, no intercourse or strenuous activity. By the next morning, if you feel fine, you could get back to your normal schedule. If you have any unusual cramps, bleeding, leakage of fluid, chills or fever, let the doctor be informed about the same.
Risks and complications of amniocentesis
There are very few risks to the mother. Risks to the baby could be divided into two viz. risks of miscarriages and risk of injuries. Injuries to the baby by the needle are exceedingly rare now since the procedure is done under ultrasound guidance. Risks of miscarriages still exist but have also come down significantly. Miscarriages might result from bleeding from the baby if one of the vessels of the baby is cut by the needle (this is very rare) or might result from an infection, rupture of the membranes, or spontaneous labor. This is the reason why we clean the skin very carefully before inserting the needle. Occasionally a baby might also die after a normal amniocentesis due to unexplained reasons.
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