An amniocentesis is an insertion of a needle through the abdominal wall into the uterus to withdraw amniotic fluid. Cells in the fluid are tested to determine if the baby is chromosomally normal.
Will the procedure hurt my baby or me?
The procedure is almost painless and has little risk for the baby. It is performed with ultrasound guidance to avoid hitting the placenta or the baby with the needle. There is a very small risk of interrupting a pregnancy or causing an early labor, but this occurs in less than 1 percent of patients.
When is amniocentesis done during pregnancy?
It depends on the purpose of the amniocentesis. If the test is ordered to confirm that the baby is developing normally, it is usually done at around three to four-and-a-half months of pregnancy. If ordered to determine that the baby's lungs are mature when an early delivery is medically needed, it is performed prior to delivery.