The time of 20 days of pregnancy and the vague pain in the stomach may be a manifestation of pre-eclampsia, abnormal shedding of endometrium and biochemical pregnancy, because the calculation of pregnancy time should start from the last menstruation, but there may be a misunderstanding of pregnancy time, so it starts from the time of intercourse. If there is obvious abdominal pain after the appearance of the gestational sac, it is possible that there is obvious bleeding around the gestational sac causing preterm miscarriage, and it is necessary to confirm the situation around the gestational sac through ultrasound examination and then to preserve the pregnancy. If there is no gestational sac, it may be a biochemical pregnancy, we need to check the level of progesterone and human chorionic gonadotropin in the body and see if the doubling of the blood HCG interval of 48 hours is normal to infer. Pay attention to rest and you can improve.