What Is Amniocentesis?
The amniotic fluid surrounding your baby in the womb contains cells from the baby’s skin, intestines, and genital and urinary systems. Amniocentesis is a procedure in which a fine needle is inserted through the mother’s abdomen into the amniotic sac under ultrasound guidance to collect about 15–25 ml of this fluid. During the procedure, specialists take great care to avoid injuring the fetus, placenta, or umbilical cord.
Amniocentesis is performed to detect genetic disorders in the unborn baby. It is particularly recommended when screening test results are abnormal, in advanced maternal age, when structural anomalies are detected on ultrasound, or when either parent is known to carry a chromosomal abnormality. The fetal karyotype (chromosomal structure) is then evaluated.
When Is It Performed for Diagnostic Purposes?
Cells obtained from the amniotic fluid are examined to identify chromosomal abnormalities. This test can also be used to:
- Assess fetal lung maturity in later stages of pregnancy,
- Determine whether blood incompatibility between mother and father is affecting the baby,
- Confirm a suspected rupture of the amniotic sac,
- Evaluate cases where amniotic fluid levels are abnormally high or low.
Amniocentesis is typically performed after the 16th week of pregnancy. Procedures done earlier carry a higher risk of complications.
When Is Amniocentesis Recommended?
Amniocentesis is advised if there is a risk of chromosomal, genetic, or structural abnormalities in the baby. Risk factors include:
- Maternal age of 35–40 years or older (higher likelihood of chromosomal abnormalities),
- History of chromosomal, structural, or genetic abnormalities in previous pregnancies,
- High-risk results in screening tests (such as first-trimester or triple screening),
- Presence of genetic disease carriers in the family (e.g., Fragile X syndrome, metabolic disorders, thalassemia).
In these situations, amniocentesis is recommended for a definitive diagnosis.
After the Procedure and Possible Complications
After amniocentesis, some mothers may experience mild pain or cramping at the needle site—similar to the brief discomfort of a blood draw.
Other possible, though uncommon, effects include:
- Slight vaginal spotting,
- Mild fluid leakage,
- Rarely, increased cramping.
It is important to rest for several hours after the procedure and avoid strenuous physical activity.
The miscarriage risk associated with amniocentesis ranges between 1 in 200 and 1 in 300.
Important Information
Expectant mothers aged 35–40 or older are strongly advised to undergo prenatal screening tests and, if necessary, amniocentesis. This allows early detection of genetic abnormalities and appropriate pregnancy management.
