In the second trimester, the fetus has not yet formed and the enlarged uterus is still in the pelvic cavity and has not grown out of the pelvis, so the belly will not increase significantly. After the third month of pregnancy, the fetus has already developed, growing fast and the uterus has enlarged and grown out of the pelvic cavity, only then will you feel your belly start to increase in size more obviously. Only in a very small number of women with multiple pregnancies, or in the event of an unplanned pregnancy such as a gravidity, the uterus will increase significantly, and may grow out of the pelvis in the second trimester, and the woman’s abdomen will increase more significantly, so go to the hospital to check if there is an unplanned situation so that you can take the appropriate treatment.