cervix, called an incompetent cervix, and most practitioners offer them something called a cervical cerclagewhich is a stitch that your physician would put around your cervix. >> mcfarland: the cervix is the lower portion of the uterus and is the doorway between the uterus and the vagina. during pregnancy, the cervix closes to help keep the fetus in the uterus. when labor occurs, the cervix dilates, or opens, to allow the baby through. in general, the cervix is normally around 4 centimeters long. this is the distance between the outside world and the fetus. the shorter the cervix, the thinner the wall between the fetus and the outside world. although rikisha's initial preterm birth was due to an infection, during her checkup for baby number two, doctors found that her cervix was shorter than normal, which helps explain why she had had six miscarriages before she was able to deliver her son, a.j. dr. andrei rebarber is the president of carnegie hill imaging and maternal fetal medicine associates, as well as clinical associate professor at mount sinai school of medicine in new york. >> her cer