Incompetent UTERINE CERVIX is usually diagnosed in the second trimester of PREGNANCY. It is characterized by passive painless cervical dilation in the absence of UTERINE CONTRACTION; BLEEDING; INFECTION; and sometimes with the amniotic sac (AMNIOTIC MEMBRANE) bulging through the partially dilated cervix. Left untreated, this condition may lead to premature pregnancy loss, such as HABITUAL ABORTION.