28 weeks is not too early for a microdiagnosis, it is a normal time frame. Generally, a micro-anomaly is done at 27 to 28 weeks, so it is normal to check for micro-anomalies at 28 weeks. The main purpose of microanomaly is to use general ultrasound system to screen the development of the fetus, and diagnose the presence of fatal malformations, such as cerebral bulging, single-chambered heart, open spina bifida, fatal chondrodysplasia, and so on. It is important to note that this test is particularly important and must be performed on medical advice. At this stage, the fetus has more space to move around in the uterus, which makes it easier to examine. Ultrasound can observe the morphology and structure of the fetal organs from multiple angles, and screen for the presence of malformations. It is recommended that you can move appropriately before the mini-exam, which will help the baby to move around in the body and facilitate the doctor’s examination.