You must sign a consent form. Your bladder must be full for the ultrasound . There are no food or fluid restrictions. If an anesthetic is used, there may be a sharp, stinging sensation for a few seconds. When the needle enters into the amniotic sac, a sharp pain lasting a few seconds may be felt.
Some women have the sensation of pressure in the lower abdomen when the fluid is withdrawn.
After the procedure there may be some minor cramping. There is a slight chance of infection or injury to the fetus. There is even a smaller chance of miscarriage . This test is typically performed when a problem is suspected, so the results outweigh the risk. Later on in a pregnancy , the test is used to identify suspected problems such as a blood group problem or infection.