Invasive Testing: Amniocentesis

CASE DESCRIPTION

Amniocentesis is a prenatal procedure in which an obstetrician samples a small amount of amniotic fluid surrounding the developing fetus under continuous ultrasound guidance.
The most common indication for amniocentesis is prenatal genetic testing. Genetic testing may include a QF-PCR or Karyotype, Chromosomal Microarray, or additional single gene, panel or whole exome/genome testing based on the specific indication.
A pre-procedure ultrasound assessment should be performed and documented to evaluate fetal well-being, fetal presentation, cervical length, and placental location.
Careful ultrasound planning of the needle insertion site is essential for procedural safety and success. An optimal site is characterized by:

Based on local institution experience, the risk of procedure-related pregnancy loss due to amniocentesis is usually quoted around 1 in 500 to 1 in 1000.
Continuous visualization of the needle path throughout the procedure is essential. A key principle of the optimal amniocentesis technique is to never advance or withdraw the needle unless the needle tip is clearly visualized.
The myometrium is punctured swiftly to minimize discomfort. Entry into the amniotic cavity should also be performed with a swift, decisive motion to avoid tenting of the amniotic membranes.

Required Equipment

Sterile cleaning solution
Sterile drapes or towels
Sterile ultrasound gel
Sterile ultrasound cover
Amniocentesis needle, typically a 22 gauge needle with removable stylet at an appropriate length to accommodate the required insertion depth
Syringes for collecting amniotic fluid
Labelled specimen tubes
Requisitions for testing
Bandage

RELATED CASES