The following are some of the most important tests that need to be done when you are pregnant: 1. You need to go to a regular hospital for an ultrasound examination at about 45 days of pregnancy, which can accurately determine whether the pregnancy is intrauterine and the number of pregnancies. 2. After the pregnancy is confirmed, you need to have a blood test to check the progesterone level in your body. If the progesterone level is too low, you need to actively receive treatment under the guidance of your doctor, otherwise it will easily lead to miscarriage. 3. In the third month of pregnancy, you need to undergo a comprehensive maternity checkup. The test will include liver function test, electrocardiogram, blood glucose test, syphilis test and white belt test, etc. 4. Down’s syndrome screening test can detect whether the fetus has congenital diseases. If the result of Down’s syndrome screening is high risk, it is better to have non-invasive DNA or amniocentesis to confirm the diagnosis. In addition, women need to have 4D ultrasound during 22-25 weeks of pregnancy to check if the fetus has any malformation or other abnormalities.