Fasting is generally not required for routine obstetric examinations at 20 weeks of pregnancy. 20 weeks pregnant obstetric examination need to check the pregnant woman’s blood pressure, weight, uterine fundal height, fetal heart rate, blood sampling test is also known as routine blood test, if you have not previously done the Down’s syndrome screening or non-invasive DNA test, at this time you can also be examined, these blood sampling items do not need fasting. You can also have a three-dimensional or four-dimensional ultrasound, which also do not require fasting. The tests that require fasting for maternity checkups during pregnancy are generally blood draws for fasting blood sugar, liver and kidney function, glucose tolerance test, etc. Other blood draws, ultrasounds, and routine health care tests do not require fasting. When the glucose tolerance test is required during the 25-28 weeks of pregnancy, fasting will be required for the test.