Amniocentesis or “amnio” usually is done after 15 weeks of pregnancy. The procedure involves obtaining amniotic fluid from around the fetus. The procedure is done through mother's abdomen with a needle under ultrasound guidance.
The amniotic fluid contains fetal cells that are used for the genetic tests. The level of AFP in the amniotic fluid is also checked, to look for neural tube defects. Genetic analysis through amniocentesis is highly accurate but occasionally results may not be obtained.
Any medical procedure has potential risks. The risks of amniocentesis include bleeding, infection, leakage of fluid, and miscarriage. The chance of miscarriage from amniocentesis is about 1 in 300. The other complications are uncommon.