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.
As you've discovered, your belly isn't the only thing expanding during your pregnancy. A pregnant body produces the hormone relaxin, which causes your pelvic ligaments and joints to loosen to make room for the baby's exit. That same hormone also relaxes the ligaments in your feet, allowing the bones to separate a bit.