What It Is
Amniocentesis is a procedure performed during pregnancy that involves collecting a small sample of amniotic fluid, the fluid surrounding a developing baby in the uterus, for further testing.
What It Checks
Amniotic fluid contains cells shed by the developing baby, which can be analyzed to check for certain genetic and chromosomal conditions. The fluid itself can also be tested for other purposes depending on the specific reason the procedure is being performed.
Why It's Used
Amniocentesis is commonly used when there's an increased likelihood of a genetic or chromosomal condition, often based on earlier screening test results, maternal age, or family history, providing more definitive diagnostic information than screening tests alone can offer.
How It's Done
During amniocentesis, a thin needle is guided through the abdominal wall and into the uterus, typically with continuous ultrasound guidance to help ensure safe and accurate placement, and a small amount of amniotic fluid is withdrawn. The fluid sample is then sent to a laboratory for detailed analysis, which can take a period of days to weeks depending on the specific tests being performed.
Background
Amniocentesis was first used for medical purposes in the mid-20th century, initially for reasons unrelated to genetic testing, before its potential for genetic and chromosomal analysis was recognized and developed further in the 1960s and 1970s. The introduction of ultrasound guidance considerably improved the safety of the procedure, and amniocentesis remains an important diagnostic tool in prenatal care today, particularly for confirming findings from earlier screening tests.