Why are prenatal vitamins important during pregnancy?

Prenatal vitamins are crucial during pregnancy primarily because they ensure adequate intake of essential nutrients, particularly folic acid and iron. Folic acid is vital for the prevention of neural tube defects in the developing fetus, which occur in the early stages of pregnancy when the spinal cord and brain are forming. Sufficient iron is necessary to support the increased blood volume during pregnancy and to prevent anemia, which can affect both the mother and the fetus.

While other options might allude to benefits associated with vitamins, they do not highlight the critical role of proper nutrient intake. For example, prenatal vitamins do not prevent morning sickness, enhance fetal movements like kicking, or directly contribute to managing weight gain during pregnancy. The primary function of prenatal vitamins is to fill gaps in a pregnant woman's diet to promote optimal health outcomes for both mother and baby, thus making the first option the correct answer.