It is normal for the belly to bulge out at 11 weeks of pregnancy. By this stage, the uterus has grown significantly and has overtaken the pelvis, so the fundus can already be felt in the belly. Some women with thick abdominal fat can already see a slight bulge in their abdomen at this point. However, pregnant women with a thin body type may not be able to see it very clearly at this stage, but when lying down, the fundus can be felt on the abdomen. This is also a critical period for fetal growth and development, and many organs and systems begin to develop slowly during this stage. Usually by 11-13 weeks, a small 4D measurement of NT thickness is needed as a preliminary screening test for fetal malformations.