In medicine,<unk>  is a condition in which a pregnant woman's cervix begins to dilate (widen) and efface (thin) before her pregnancy has reached term.<unk>  is a cause of miscarriage and preterm birth in the second and third trimesters.
In a woman with<unk> , dilation and effacement of the cervix occur without pain or uterine contractions. Instead of happening in response to uterine contractions, as in normal pregnancy, these events occur because of weakness of the cervix, which opens under the growing pressure of the uterus as pregnancy progresses. If the changes are not halted, rupture of the membranes and birth of a premature baby can result. According to statistics provided by the Mayo Clinic,<unk>  is relatively rare in the United States, occurring in only 1—2% of all pregnancies, but it is thought to cause as many as 20—25% of miscarriages in the second trimester.
Cervical incompetence
Uterine prolapse
Unwanted pregnancy
Pregnancy termination complications
Premature birth
Dysfunctional uterine bleeding
Preterm labour
Multiple birth