The average pregnancy is not considered stable until about 12 weeks. After 12 weeks of pregnancy into the middle of pregnancy, the embryo is more stable. Under normal circumstances, the first trimester of pregnancy, that is, within 12 weeks of pregnancy, belongs to the early stage of pregnancy, at this time the embryo is not very stable, you should avoid strenuous exercise, pay attention to rest, reasonable diet, folic acid supplementation, to avoid contact with harmful and toxic substances, such as the need for medication to consult a professional doctor. After the third month of pregnancy, most of the embryos have been stabilized, will enter the middle of pregnancy, women can be appropriate sex, but also to do a good job in other aspects of care. In addition, after pregnancy should be reasonable rest, regular medical pregnancy checkups, after the emergence of abnormalities should also be timely medical examination and treatment.