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Chorionic Villus Sampling
Aka: Chorionic Villus Sampling
- See Also
- Antenatal Screening
- Definition
- Definitive, first trimester Antenatal Screening for fetal chromosomal abnormalities
- Indications
- Antenatal Screening for fetal chromosomal abnormalities for high risk pregnancies
- Protocol
- Performed between 10-13 weeks gestation
- Placental tissue sampling techniques
- Transabdominal sampling
- Transcervical sampling
- Higher Incidence of pregnancy loss than with abdominal sampling
- Indicated if placenta posterior or bowel blocks abdominal sampling
- Adverse Effects
- Pregnancy loss
- Risk: 0.6 to 4.6% (higher rate than with Amniocentesis)
- Limb reduction defects
- Gestational age 10-13 weeks: Risk does not exceed general population risk (6 per 10,000)
- Gestational age <10 weeks: 1-2% risk of limb reduction defect
- Efficacy: Down Syndrome detection
- Test Sensitivity: 97.8%
- Test Specificity: 98-99%
- References
- Anderson (2009) Am Fam Physician 79(2): 117-24
- Caughey (2006) Obstet Gynecol 108: 612-6