Cervical weakness, also called cervical incompetence or cervical insufficiency, is a medical condition of pregnancy in which the cervix begins to dilate (widen) and efface (thin) before the pregnancy has reached term. Definitions of cervical weakness vary, but one that is frequently used is the inability of the uterine cervix to retain a pregnancy in the absence of the signs and symptoms of clinical contractions, or labor, or both in the second trimester.[1] Cervical weakness may cause miscarriage or preterm birth during the second and third trimesters. Another sign of cervical weakness is funneling at the internal orifice of the uterus, which is a dilation of the cervical canal at this location.[2]