Solution: A short cervix is defined as a length 25 mm or shorter at 24 weeks and increases the risk of preterm delivery by 6 fold. In this case, there is "funneling" of the cervix and you could actually watch the fetus' foot move in and out of the cervical canal (seen on images). A very full bladder can obscure this issue, so it is important to evaluate the cervix either early in the examination before the bladder is too full, or after voiding at the end of the examination. If there is any question, TV or translabial imaging should be performed with an empty bladder to confirm. Incompetence is defined as not only shortening of the cervix, but in addition, opening of the internal os to at least 3 mm. This is a common cause of pregnancy failure in the second trimester. V-shaped funneling has a higher likelihood of preterm labor than U-shaped funneling.