Pain in the abdomen like menstruation when you are newly pregnant may be a physiological pain caused by pregnancy. If the pain does not disappear for a long time, or even gets worse, and is accompanied by vaginal bleeding, the possibility of ectopic pregnancy or pre-eclampsia cannot be ruled out, and the cause needs to be identified and treated. In the early stage of pregnancy, the uterus enlarges, the pelvic cavity becomes engorged with blood, and the estrogen level rises, causing the tissues and ligaments around the uterus to be stretched, resulting in pain in the abdomen like menstruation. But this pain will soon be relieved and will not bring too much pain, at this time the pregnant woman can pay attention to rest. If rupture occurs, it can be accompanied by vaginal bleeding and tearing pain, which requires immediate medical intervention. 2. Pre-eclampsia: If the luteinizing body function is abnormal, resulting in progesterone value lower than the normal level, it may lead to the precursor of miscarriage, accompanied by pain in the abdomen, resembling dysmenorrhea, which requires timely hospital treatment for birth control. During early pregnancy, the embryo is not yet stable, so no matter which cause of abdominal pain, you need to go to the hospital for examination in time, through ultrasound, blood hCG and progesterone for clarification, and the doctor will give reasonable advice or treatment according to the examination results.