Final answer:
A major advantage of chorionic villus sampling over amniocentesis is that it can be performed earlier in the pregnancy for faster results. However, CVS has a slightly higher risk of miscarriage and can't detect some conditions that amniocentesis can.
Step-by-step explanation:
Major Advantages and Disadvantages of Chorionic Villus Sampling Over Amniocentesis
A major advantage of chorionic villus sampling (CVS) over amniocentesis is the timing of the procedure. CVS can be performed earlier in the pregnancy, typically between the 10th and 12th weeks, allowing for earlier detection of genetic abnormalities. This could provide more options for parents making decisions about their pregnancy. In contrast, amniocentesis is usually conducted later, between the 15th and 18th weeks of pregnancy.
A major disadvantage of chorionic villus sampling, however, is the slightly higher risk of miscarriage compared to amniocentesis. Additionally, CVS cannot detect certain abnormalities that amniocentesis can, such as neural tube defects, since it tests placental tissue rather than amniotic fluid which contains fetal cells. Therefore, while CVS provides earlier results, it comes with increased risks and limitations in the breadth of detectable conditions.