Whether you can have a checkup the next day after having sex on the first day depends mainly on the content and items of the checkup. If there is sex on the first day, the next day is to carry out ultrasound, gastroscopy, colonoscopy, CT and other tests, are OK, no effect. However, if the next day the woman is going to have a gynecological examination, such as laboratory tests of routine leukorrhea, cervical TCT, HPV screening, etc., it is not suitable. This is because having sex on the first day will change the internal environment of the woman’s vagina, which will have a certain impact on the results of the examination. For routine gynecological examinations, it is generally recommended that coitus is not advisable within 3 days before the examination. In addition, if a man has sex on the first day and wants to have a sperm quality test the next day, it is also not allowed. If having sex on the first day may lead to a decrease in the vigor and quality of sperms, the results of the test may be inaccurate at that time. Therefore, it is generally recommended that men abstain from sexual intercourse for 2-3 days before the test.