What is the function of the mucus plug in the cervix?

The function of the mucus plug in the cervix is primarily to protect the uterus from infection. This dense and thick secretion forms a barrier at the entrance of the cervix during pregnancy, helping to seal the uterus and prevent harmful bacteria and other pathogens from entering and possibly causing an infection that could harm both the mother and the developing fetus. The presence of the mucus plug is crucial in maintaining a safe environment for fetal development until birth is near, at which point the plug is typically expelled in preparation for labor.

While the mucus plug does not facilitate sperm entry, provide oxygen to the fetus, or regulate labor contractions, its protective role is vital in maintaining the health and safety of the pregnancy.