When Is Amniocentesis Performed and How Is It Done?
Amniocentesis is performed between the 16th and 20th weeks of pregnancy. Its purpose is to determine whether the baby has chromosomal abnormalities such as Down syndrome. Under ultrasound guidance, a needle is carefully advanced toward the amniotic sac at a safe distance from the baby.
In about 8 out of every 100 women, not enough fluid can be collected on the first attempt, so the needle must be repositioned. This depends on the baby’s position. If the second attempt is also unsuccessful, the patient may be asked to return the next day.
If the mother’s blood type is RH negative (−), an anti-D injection is recommended after the procedure to prevent blood group incompatibility.