II. Definition
- Definitive, second trimester Antenatal Screening for fetal chromosomal abnormalities
III. Indications
- Antenatal Screening for fetal chromosomal abnormalities for high risk pregnancies
IV. Protocol
- Timing
- Safest time period: 16-18 weeks gestation
- Range of sampling time: 14-20 weeks gestation
- Technique
- Amniotic fluid sampled transabdominally under Ultrasound guidance
V. Adverse Effects
- Pregnancy loss (0.3 to 1% risk)
- Vaginal spotting
- Amniotic fluid leak
- Chorioamnionitis
- Fetal injury from Amniocentesis needle
- Failed procedure in which fetal cells in amniotic fluid do not grow in culture
VI. Efficacy: Down Syndrome detection
- Test Sensitivity: 99.4%