Normally, if you usually have regular menstruation with a cycle of 28-30 days, you can usually see the gestational sac by ultrasound at around 6 weeks of pregnancy. After pregnancy, usually around 6 weeks of pregnancy, ultrasound can indicate the double ring sign and the gestational sac can be seen, suggesting early intrauterine pregnancy, which belongs to the beginning of pregnancy and requires regular and good maternity checkups. For example, NT test is needed around 12 weeks of pregnancy, Down’s syndrome screening is needed around 16 weeks of pregnancy, systemic ultrasound and glucose tolerance screening is needed around 24 weeks of pregnancy, etc. Secondly, if you have not taken folic acid before pregnancy, you should start taking it regularly to ensure the normal growth and development of the fetus. After pregnancy, you must pay attention to regular work and rest, ensure sufficient sleep, avoid staying up late, overwork and strenuous exercise. You should pay attention to balanced nutrition, eat less cold, spicy and stimulating food, quit smoking and drinking, and be careful with drugs.