What is the role of maternal antibodies during pregnancy?

Maternal antibodies play a crucial role in providing passive immunity to the fetus during pregnancy. This occurs primarily through the placenta, where maternal immunoglobulin G (IgG) antibodies are transferred to the fetus. This transfer begins as early as the second trimester and continues until birth, providing the developing fetus with immunity against various infections and diseases that the mother has encountered before and during pregnancy.

Additionally, this passive immunity is vital because it offers the newborn protection during the early months of life when the infant's own immune system is still developing. It helps shield the baby from pathogens and boosts the infant's ability to fight infections until it can produce its own antibodies in response to vaccines and infections.

While the other options are relevant to the maternal-fetal relationship, they do not directly relate to the specific role of maternal antibodies. For instance, enhancing maternal health or promoting fetal growth involves different physiological mechanisms, and uterine contractions are primarily managed by hormonal changes and not directly influenced by maternal antibodies. The main role of maternal antibodies is indeed to provide this critical passive immunity to the fetus, ensuring it is somewhat protected in the early days after birth.