incompetent cervix: (obstetrics) uterine cervix that becomes dilated before term and without labor often resulting in miscarriage or premature birth
cervix: necklike opening to the uterus
body mass index: a measure of someone's weight in relation to height; to calculate one's BMI, multiply one's weight in pounds and divide that by the square of one's height in inches; overweight is a BMI greater than 25; obese is a BMI greater than 30