A biochemical pregnancy is usually followed by menstruation in about one month. A biochemical pregnancy occurs when the sperm and egg unite to form a fertilized egg, and after the secretion of human chorionic gonadotropin, the fertilized egg does not settle and grow normally, and the gestational sac is not visible on ultrasound. A biochemical pregnancy may or may not bleed. If a biochemical pregnancy bleeds, it can be treated as a menstrual period, so the next period should usually be about one month after the biochemical pregnancy bleeds. However, it is important to note that because human chorionic gland promoting hormone (HCG) is elevated in a biochemical pregnancy, although it is later reduced, it is important to be alert for rebound elevations in HCG, which may turn into trophoblastic disease and require hospitalization if they occur. In addition, couples who are preparing for pregnancy should stop smoking and drinking, increase physical exercise and change bad habits to effectively reduce the risk of biochemical pregnancy.