Microdiagnosis and 4D are not the same test, they are both tests that utilize ultrasound, but the purpose of the test is different. A mini-diagnostic is generally a screening test that is performed when the fetus is around 28 weeks of pregnancy. A major fetal exclusion is performed around 24 weeks of gestation. Both the first and the second drainage are very important and are tests done to detect structural malformations in the fetus. The mini-detection can be performed using a two-dimensional, three-dimensional or four-dimensional ultrasound. The 4D can use ultrasound to show a three-dimensional image of the fetus in the womb and may be useful in screening for malformations. Pregnant women need to follow their doctor’s instructions for regular checkups to ensure the health of their baby.