**Question:** Chorionic villous sampling done before 10 weeks may result in:

1. Core Concept: Chorionic villous sampling (CVS) is a prenatal diagnostic procedure used to test for genetic abnormalities and infections in the fetus. It involves obtaining a sample of the chorionic villi (tissue growths on the placenta) from the first or second trimester.

2. Why the Correct Answer is Right: Chorionic villous sampling done before 10 weeks gestation carries a higher risk due to the immaturity of the fetus and the associated complications.

3. Why Each Wrong Option is Incorrect:
A. This option is incorrect because the procedure is generally performed before 10 weeks to achieve a higher success rate and minimize the risk of miscarriage.
B. This option is incorrect as the procedure is done before 10 weeks for diagnostic purposes, specifically to detect genetic abnormalities and infections in the fetus.
C. This option is incorrect because CVS is a prenatal diagnostic procedure performed before 10 weeks to detect fetal anomalies or infections.
D. This option is incorrect as CVS is a minimally invasive diagnostic procedure done before 10 weeks for early detection of fetal anomalies or infections.

4. Clinical Pearl: Early CVS (before 10 weeks) has a higher risk of miscarriage due to fetal immaturity. However, it offers a higher diagnostic success rate and allows for early detection of fetal anomalies and infections. This makes it a valuable diagnostic tool, especially when necessary for informed decision-making and preemptive interventions.

5. Correct Answer: D. Chorionic villous sampling (CVS) is a minimally invasive prenatal diagnostic procedure performed before 10 weeks for early detection of fetal anomalies or infections.

6. Core Concept: CVS is performed during the first trimester to obtain a sample of chorionic villi, which are specialized villi present on the placenta. This allows for early detection of genetic abnormalities, infections, and other fetal anomalies.

7. Clinical Pearl: CVS before 10 weeks carries a higher risk of miscarriage due to fetal immaturity. However, it provides a higher diagnostic success rate, enabling informed decision-making and timely interventions for the well-being of the mother and the fetus.