The time when women gain weight rapidly during pregnancy is usually during the mid-pregnancy period, i.e. between 4 and 7 months of pregnancy. Usually women do not gain weight significantly in the early pregnancy stage, and the fetus is just developing in the third month of pregnancy, most women may gain about 1kg or 2kg during this period. If a pregnant woman has a strong early pregnancy reaction, with obvious vomiting, nausea, loss of appetite, etc., she may also experience weight loss. In the middle stage of pregnancy, not only the fetus is gradually developing in the womb, but also the mother’s fat and amniotic fluid are gradually increasing, so the pregnant woman’s weight will increase significantly at this time. In the late stages of pregnancy, the fetus is maturing and the mother herself does not gain much weight. Therefore, women do not need to be too concerned about their weight during pregnancy, as long as they can ensure adequate nutrition and normal fetal development.