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.
When you are pregnant, prolactin changes are completely normal. In fact, your prolactin must increase in order to encourage the production of milk in your mammary glands. During pregnancy your hormones are all over the place. In particular, your estrogen levels begin to rise, and this is what stimulates the increase in your prolactin levels.