Cervical incompetence is defined as spontaneous dilation of the cervix leading to pre-term birth. It is caused by weakening or shortening of the cervical length below normal ranges of 3-4.5 cm. Diagnosis involves measuring cervical length via transvaginal ultrasound and identifying funneling of the cervical os. Treatment options include cervical cerclage to stitch the cervix closed and progesterone supplementation to prevent pre-term birth. Precise diagnosis can be challenging due to factors like overfilled bladders compressing the cervix.