An amniocentesis is a specific type of prenatal test that is performed some time during the second trimester, typically between week fifteen and week eighteen of pregnancy.  An amniocentesis is designed to detect a variety of potential problems with your pregnancy.  Specifically, an amniocentesis is typically used by a doctor in order to detect defects of the chromosomes, such as Down Syndrome.

 

 

Prior to having an amniocentesis, you will probably have a detailed ultrasound.  This ultrasound will measure your baby, and will also help determine the placement of the baby and the amniotic sac.  In some cases, this ultrasound will occur even days ahead of the amniocentesis. 

 

 

When you come in for your amniocentesis, you will start out by laying on a table.  Your abdomen will be cleaned using alcohol or iodine.  After this, your amniotic sac will be located with an ultrasound.  They will need to find a pocket of amniotic fluid that is far away from the baby and the placenta.  Because of this, it can take quite a while for this portion of the procedure.  Once the ultrasound locates a good spot, a long, hollow, thin needle will be inserted through the wall of your abdomen and into the amniotic sac.  Around an ounce of fluid will be removed.  After this, the needle will be removed.  The removal of amniotic fluid should take less than a minute.

 

 

An amniocentesis can be uncomfortable, and you might feel cramping, pressure, or pinching.  You may have anesthetic on your abdomen during the procedure.  Typically, after the procedure, your doctor will listen to your baby’s heart to make sure that everything is OK.  If you were to have significant cramping, spotting, or if you are leaking fluid after your amniocentesis, you should contact your health care provider.

Why is my doctor recommending that I have an amniocentesis?