The contractions include anal and urinary sphincter contractions, the smooth muscles in the inward portion of the vagina contraction, the puboccocceygeus muscle contraction, the uterine contractions w...The contractions include anal and urinary sphincter contractions, the smooth muscles in the inward portion of the vagina contraction, the puboccocceygeus muscle contraction, the uterine contractions which cause the uterus and cervix to dip down into the vagina, and general muscles contractions in the body.