At which month does your belly start to get harder and it getting bigger under button?

Around the fourth month of pregnancy, the uterus (womb) begins to rise out of the pelvis and into the abdomen. This is when most women start to "show" or look visibly pregnant. The belly will continue to grow and get harder as the pregnancy progresses. By the end of pregnancy, the uterus will have grown to about 20 times its original size and will be filled with amniotic fluid and the developing fetus.