Usually, the opening of the uterus will be faster than that of the first birth, but due to the differences in the physical condition of each pregnant woman and the fetus, the opening time of the uterus will be different.1. The opening of the uterus will be faster: the third birth belongs to a woman who is pregnant, and the labor progresses faster, and the cervix will be relatively lax; when the uterine contraction is normal, with the uterine contraction and the descending of the head of the fetus, the cervical canal will gradually shorten on one side, and the other will gradually be opened, which will result in a shorter time for the opening of the cervix than the first birth. The opening time of the cervix will be shorter than that of the first labor; 2. The opening time of the cervix is slower: if the interval between the birth of the third child and the first two children is too long, the cervix may become tough and difficult to dilate. In addition, if the mother has medical or surgical complications, or if the fetus is too large, or even if the placenta is in an abnormal position, it is easy to prolong the opening time of the uterus, and if necessary, it is necessary for the doctor to intervene and treat the situation, or even to terminate the pregnancy by cesarean section. Pregnant women with multiple pregnancies need to be ready for labor at any time during the second trimester of pregnancy. Mothers need to move around appropriately during pregnancy to promote the dilation of the uterine opening and shorten the duration of labor. Ensure that you eat a light diet, eat more fresh vegetables and fruits, and keep your mood happy. In the second trimester of pregnancy, if there is redness, stomach drop, backache, breaking amniotic fluid, etc., you need to go to the hospital in time to wait for labor.