You can check if you are pregnant if your period is delayed for 4 days, but everyone is different, some people may be able to detect pregnancy after 7-10 days of delayed menstruation, while others may be able to detect it after 4 days or so, depending on the woman’s physical condition. If you can’t detect pregnancy with pregnancy test paper or pregnancy stick after 4 days of delayed menstruation, you can go to the hospital for a blood HCG test, or wait for 7 days of delayed menstruation to go to the hospital for a retest, which will be able to determine whether you are pregnant or not. The human chorionic gonadotropin (HCG) in the body will change about 7 days after intercourse, and you can determine whether you are pregnant or not. After having intercourse for a while, you should pay attention to your body’s symptoms to see if there is any obvious early pregnancy reaction.