Praxis Health Education (5551) Practice Test

The placenta plays a crucial role in delivering nourishment to the fetus throughout the entire pregnancy, including the second stage. During this stage, the placenta facilitates the exchange of nutrients, oxygen, and waste products between the maternal and fetal blood supply. It acts as a lifeline for the developing fetus, ensuring that essential nutrients such as glucose, amino acids, and fatty acids are efficiently transferred from the mother to support fetal growth and development.

In contrast, the other options reflect functions that are either secondary or do not primarily occur during the second stage of pregnancy. For example, while the placenta does contribute to the immune defense and some waste elimination, its primary and most critical function is nutrient delivery, especially as the fetus undergoes rapid development during this period. The regulation of sleep patterns is not a role of the placenta at all, as that involves neural and hormonal factors from the developing fetus.