AmniocentesisTest—PrenatalGeneticTesting
Written & medically reviewed by Dr. Shaivalini Kamarapu
MBBS · MS (Obstetrics & Gynaecology) · Fellowship in Reproductive Medicine · 20+ years of clinical experience
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Years of Experience
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Happy Families
Whatisanamniocentesistest?
Amniocentesis is a prenatal test in which a small amount of amniotic fluid — less than an ounce — is removed from the sac surrounding the foetus for testing. A fine needle is guided through the abdomen and into the uterus under ultrasound guidance to collect the sample.
Optimal timing
16–18 weeks
Whyisitperformed?
A positive result on a prenatal screening test like the Dual, Quadruple Marker, or NIPT
A previous baby with a chromosomal condition such as Down syndrome
A family history of a specific genetic condition
Advanced maternal age (over 35 years)
Evaluating the baby for a possible infection
Therapeutic drainage in cases of polyhydramnios, to reduce excess amniotic fluid
Howtoprepare
Disclose and discuss all current medications — some may need to be paused before the procedure
Consider bringing someone along for emotional support and to drive you home
You'll need to sign a consent form before the procedure
What to expect afterward
Mild uterine cramping, light spotting, or a few drops of amniotic fluid loss can occur immediately afterward — this is normal. Seek medical advice if you notice persistent fluid leaking from the vagina, heavy bleeding, severe abdominal pain, or fever.
Possiblecomplications
Miscarriage
Occurs in roughly 1 in 300 to 1 in 500 procedures, usually within the first 5 days. Risk is higher if the procedure is done before 15 weeks, BMI is above 40 kg/m², there's been vaginal bleeding earlier in the pregnancy, or a history of previous miscarriage.
Leaking amniotic fluid
Rare.
Infection
Rare, though mother-to-baby transmission is a specific concern if the mother has Hepatitis C or toxoplasmosis.
Needle injury
Rare.
Whencanyouexpectresults?
2–3 weeks
Karyotyping
3–5 days
QF-PCR