At least eight prenatal checkups are required during pregnancy. The first prenatal checkup is at about 12 weeks to establish a perinatal health book, determine the week of pregnancy, project the expected date of delivery, assess risk factors during pregnancy, measure blood pressure and weight, and perform gynecological examinations; routine blood and urine tests, blood type, fasting glucose, liver and kidney function, and tests for infectious diseases; ultrasound is performed to understand the size of the gestational sac and the location of the bed, and to determine the week of pregnancy. At 14-19 weeks, a Down’s syndrome screening test is also performed. During the second prenatal visit, between 14 and 19 weeks, if there is a high risk for Down’s syndrome, a routine non-invasive DNA or amniocentesis will be performed. For the third prenatal visit, a 4D ultrasound, routine blood and urine tests are routinely performed at 20-24 weeks. For the fourth prenatal visit, screening for gestational diabetes is performed at 25-28 weeks, and routine blood and urine tests are again performed. The fifth prenatal checkup, usually at 29-32 weeks, is to measure blood pressure, uterine height and abdominal circumference, and to perform obstetric ultrasound to understand the growth and development of the fetus, and to perform routine blood and urine tests. The sixth prenatal checkup, at 33-36 weeks, routine urine tests, B strep tests and routine leucorrhoea tests may be performed. The seventh prenatal checkup, usually at 37-41 weeks of pregnancy, is another obstetric ultrasound to understand the fetal growth and development and to monitor the fetal heartbeat.