There are no clear statistics on how long it takes for the opening of the uterus after a contraction. Also, because of the different nature of contractions, the mouth may not open after contractions and needs to be analyzed by situation. If a pregnant woman has not reached her due date, she is usually considered to have pseudo contractions, which are characterized by inconsistent contraction frequency, short duration, long intervals and irregularity; contractions are sometimes strong and sometimes weak; they are not accompanied by morphological changes of the cervix such as shortening of the cervical canal and dilatation of the uterine opening. For a full-term pregnant woman, the contractions are regular contractions of the uterus. The exact duration of the contractions before the opening of the uterus varies from person to person and cannot be generalized, but the expansion of the uterus with regular contractions has certain characteristics. When a pregnant woman is in labor, the intensity of contractions will gradually change from weak to strong in order to facilitate the delivery of the fetus. The contractions are initially about once every 30 minutes and last for about 20 seconds. When the contractions gradually start to occur once every 5 minutes or even shorter, it generally indicates that the opening of the uterus is gradually starting to dilate. If a pregnant woman has contractions when she is not yet full term, they are often considered to be pseudo contractions and generally do not require special treatment; if a pregnant woman has contractions when she is in labor, she should seek medical attention and make preparations for labor.