Realism is a good thing to have when writing it adds believability and convinces your reader that you know what your talking about. XXX You do know that the same opening allows an 8 lb. During pregnancy it can go from inches thick while protecting the fetus, to paper thin in a matter of hours when in labor. child to pass through it during child birth, right? Realism is a good thing to have when writing it adds believability and convinces your reader that you know what your talking about. The reason a child can pass through is due the massive release of the hormones oxytocin and pitocin which cause uterine contractions that make it possible for the fetus to pass through the cervical opening.




















