It is easy to bloat when you are 18 weeks pregnant may be normal, with the gastrointestinal peristalsis weakened, the uterus enlarged compression related, or may be abnormal, such as indigestion. 1. weakened gastrointestinal peristalsis: after pregnancy due to changes in hormone levels in the body, may affect the intestinal peristalsis slows down, intestinal tension is weakened, food debris and feces in the large intestine stays longer, the rectal venous pressure increases, easy to bloat symptoms, this is a normal phenomenon. 2. Uterus enlargement compression: after pregnancy with the increase of gestational weeks, 18 weeks pregnant uterus will slowly increase, increase the uterus so that the pelvic organs, diaphragm uplift, organ activity space is reduced, will often appear bloated stomach phenomenon, is also normal. 3. Indigestion: 18 weeks pregnant with functional dyspepsia, which can cause a functional decline in the digestive system, tissues, intestinal flora imbalance, not timely decomposition, transformation of food, there may be symptoms of bloating, this situation is generally not normal. Flatulence in 18 weeks of pregnancy occurs frequently, accompanied by other discomforts to go to the hospital for treatment.