This is very rare. Almost all amniocentesis performed nowadays is done under ultrasound control-so the doctor doing the procedure is watching the needle constantly as it is inside the womb. Doing this means that if the baby moves towards the needle, the needle can be withdrawn a little or moved into a different position. The only real risk of damage to your baby is through miscarriage-which happens in about 1% of amnios, even when the procedure is carried out perfectly, with no problems evident at the time. This is thought to be due to the introduction of bacteria into the amniotic cavity that then cause infection.
Amniocentesis: Guiding the needle
First, to help the doctor be absolutely precise when inserting the needle, an ultrasound scanner is used to establish the exact position of the fetus and the placenta. Second a fine needle is inserted into the womb and into a pool of amniotic fluid.