What is the primary function of the placenta during pregnancy?

Answer Details

The placenta is a temporary organ that develops in the uterus during pregnancy and serves as the vital interface between the mother and the developing foetus. Its primary function is to supply oxygen and nutrients from the mother's blood to the foetus and to carry waste products (such as carbon dioxide and urea) from the foetus back to the mother's circulation for disposal.

This exchange occurs across the placental barrier, where maternal and foetal blood come into close proximity without mixing directly. Oxygen and dissolved nutrients (glucose, amino acids, vitamins, and minerals) diffuse from the mother's blood into the foetal blood through the chorionic villi, while waste products move in the opposite direction.

While the placenta does produce hormones (such as progesterone and human chorionic gonadotropin) that help maintain pregnancy, this is a secondary function - not its primary one. The question asks specifically about the primary function, which is the life-sustaining supply of oxygen and nutrients to the foetus. Cushioning the foetus from external shocks is the role of the amniotic fluid, not the placenta. The placenta supplies the foetus, not the mother, so the option referring to providing nutrients to the mother misidentifies the direction of transfer.