How does an incompetent cervix harm a pregnancy?
Not medical advice: An incompetent cervix can be harmful to a pregnancy as the cervix is supposed to remain closed during the pregnancy to protect the fetus. If the cervix opens before it should, it could result in a miscarriage or pre-term labor.
The cervix is the opening to the uterus and typically will remain closed and be blocked by a mucus plug until labor begins. Once labor does begin, the cervix dilates and effaces to allow the baby to pass from the uterus into the vagina. If a doctor determines that a woman has an incompetent cervix, s/he might suggest a cervical cerclage, whereby stitches are placed in the cervix to keep it closed.