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.
You will probably start to be aware of something when you're about 18 to 22 weeks pregnant (Gillieson et al 1984) , although it can be later. If you've had a baby before, you'll know the tell-tale signs. You'll possibly start to notice your baby moving around between 15 and 18 weeks (Gillieson et al 1984) .