What is CVS (Chorionic Villus Sampling) used to determine?

Chorionic Villus Sampling (CVS) is a prenatal diagnostic procedure used primarily to assess the risk of genetic conditions in a developing fetus. During this process, a small sample of tissue (the chorionic villi) is taken from the placenta, which contains genetic material from the fetus. This allows for the analysis of the fetus's chromosomes and can help identify genetic disorders, including Down's syndrome, cystic fibrosis, and other chromosomal abnormalities.

The procedure is usually performed within the first trimester of pregnancy and is particularly useful for couples who have a known genetic risk or a family history of genetic disorders. The results from CVS can provide critical information about the health of the fetus early in the pregnancy, enabling couples to make informed decisions about their pregnancy.

In contrast, the other options pertain to different health concerns that are not determined by CVS. For instance, gestational diabetes is assessed through glucose tolerance tests rather than genetic testing. Iron deficiency is typically evaluated through blood tests that measure hemoglobin and ferritin levels. Lastly, amniotic fluid levels are usually assessed via ultrasound measurements, not CVS. Therefore, the primary purpose of CVS is to evaluate genetic risks, making it the correct answer.