What is the ring of muscle that keeps the baby in place?

The ring of muscle that helps keep the baby in place during pregnancy is called the cervix. The cervix is the lower part of the uterus that connects to the vagina and remains tightly closed to support the developing fetus. It undergoes changes as pregnancy progresses, softening and dilating in preparation for labor. This function is crucial for maintaining pregnancy and ensuring the baby is securely positioned until birth.