What are the diagnostic criteria for cervical insufficiency in the mother?

Patient's question:

No

Doctor's answer:

Cervical insufficiency is also known as "incompetent internal os" or "cervical insufficiency." The muscles and connective tissues of a woman's cervix are arranged in a spiral pattern, similar to a knot used to tie a burlap bag—it can loosen or tighten. This function is regulated by sex hormones: estrogen promotes relaxation of the cervical os muscles, while progesterone promotes contraction. Therefore, during the pregnancy period when progesterone is dominant, the cervical os is contracted. If this function is impaired, it may lead to cervical os relaxation and result in miscarriage.
The causes of cervical insufficiency include congenital and acquired factors. Congenital causes primarily involve underdevelopment or malformation of the cervix, while acquired causes include mechanical manipulation and trauma, mainly cervical canal damage caused by surgery and childbirth injuries. Thus, excessive induced abortions and cervical dilation procedures carry a risk of cervical insufficiency.
It cannot be said that cervical insufficiency is the main cause of mid-to-late miscarriage, after all, miscarriage caused by inflammatory infections is still relatively common.