4 weeks before 28 weeks of pregnancy, 2 weeks between 28 and 36 weeks of pregnancy, 1 week after 36 weeks of pregnancy; 7 weeks of pregnancy: transvaginal ultrasound, fasting blood sugar (normal before pregnancy is not necessary), thyroid function, 13 weeks of pregnancy ultrasound (NT); 7-13 weeks of pregnancy: stage I Down’s syndrome screening (optional for stage I and II); 13 weeks of pregnancy: NT ultrasound, 20 weeks of pregnancy prenatal ultrasound level III (large fetus) In fact, there are very few real problems, and it is enough to do level II for those who have problems, no matter how many levels there are, it is impossible to have 100% detection rate), and open the pregnancy certificate for the birth certificate, and make up calcium routinely; 14-21 weeks of pregnancy: stage II Down’s syndrome screening, which is also the time for non-invasive prenatal diagnosis (singleton only); 16 weeks of pregnancy Week 16: Pregnancy certificate and maternity insurance; Week 16-17: Bring all birth certificates, maternity insurance and ID cards of both spouses to the maternity office on the 5th floor of the clinic to build a file, routine laboratory tests (blood group, blood routine, urine routine, four coagulation items, biochemistry of maternity (liver and kidney function), obstetric A-function screening, hepatitis B pair, hepatitis C IgG, three STDs, routine of geodystrophy (for both spouses), serum iron II), appointment for pregnancy 30 weeks of pregnancy: Level II prenatal ultrasound; 18-27 weeks of pregnancy: amniocentesis if there are indications for prenatal diagnosis, and genetic test for geodystrophy if one of the spouses has abnormalities; 20 weeks of pregnancy: Level III prenatal ultrasound; 24-28 weeks of pregnancy: OGTT; 28 weeks of pregnancy: self-counting fetal movements; 30 weeks of pregnancy: Level II prenatal ultrasound, 38 weeks of pregnancy: Level I prenatal ultrasound; 34 weeks of pregnancy: high-risk pregnancy 36 weeks of gestation: weekly fetal heart monitoring started; 36 weeks of gestation: weekly fetal heart monitoring started in low-risk pregnancy; 38 weeks of gestation: level I antenatal ultrasound; 39 weeks of gestation: timing of elective cesarean section; 41 weeks of gestation: uncommitted labour admitted to hospital for labour.