Chorionic villus biopsy is done in all of the following EXCEPT (AIPG 2008)
|A||Neural tube defects|
|B||Sickle cell disease|
Neural tube defects
1. Indications of Chorionic villus biopsy:
a. Karyotyping is the most common indication—Down syndrome
b. Hemoglobinopathies—Sickle cell disease, Thalassemia, etc.
c. Biochemical studies—Gaucher’s disease, Niemann-Pick disease, Tay-Sach’s disease, etc.
d. Single gene defects—Myotonic dystrophy, Cystic fibrosis, Huntington’s disease, Phenylketonuria, etc.
2. Neural tube defects are diagnosed by ultrasound and estimation of alpha-fetoprotein in maternal serum/ amniotic fluid.
3. Chorionic villous biopsy can be done after 10th week (earlier than amniocentesis)
a. Earlier results reduce maternal stress by going for a possible therapeutic abortion (if indicated) at an early stage.
4. Initially a trans-cervical route is acceptable to take the sample.
a. A trans-abdominal route is taken if the pregnancy exceeds 12th week.