Fimbriae (common pili) and flagella on the surface of bacterial cells. Left: dividing Shigella enclosed in fimbriae. The structures are probably involved in the bacterium's ability to adhere to the intestinal surface. Right: dividing pair of Salmonella displaying both its peritrichous flagella and its fimbriae.
Relaxin's peak is reached during the 14 weeks of the first trimester and at delivery. It is known to mediate the hemodynamic changes that occur during pregnancy, such as increased cardiac output, increased renal blood flow, and increased arterial compliance.
The hormone progesterone is one of the main causes of excess gas during pregnancy. As your body produces more progesterone to support your pregnancy, progesterone relaxes muscles in your body. This includes the muscles of your intestine. Slower moving intestine muscles mean that your digestion slows down.