When does gas start during pregnancy?

Gas and bloating are common during pregnancy and they usually start in the second trimester. They are caused by the increased levels of progesterone, a hormone that relaxes the muscles in the body, including those in the digestive tract. This relaxation can slow down digestion and cause gas to build up. Additionally, the growing uterus can put pressure on the intestines and stomach, which can also contribute to gas and bloating.