If you are 40 days pregnant and have abdominal pain like menstrual cramps, it depends on whether it is combined with vaginal bleeding, if there is no vaginal bleeding, it may be physiological. After pregnancy, the gestational sac reaches the uterine cavity, there will be physiological pain in the lower abdomen, similar to the pain of women’s menstruation, if it can be relieved after rest, there is no need to worry. If the pain is not relieved after rest, it is necessary to go to the hospital for examination, mainly to see if there are symptoms of pre-eclampsia. If the abdominal pain is confirmed to be intrauterine pregnancy, attention should be paid to bed rest, reduce all unnecessary activities, avoid straining, and not to have conjugal life. If the abdominal pain continues to worsen and there is vaginal bleeding, you must apply birth control drugs to avoid miscarriage.