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.
A bitch that is negative for relaxin on the initial test, performed at 22-27 days post breeding, should be tested again 1 week later to confirm the negative results. Repeat testing is especially important in the early stages of pregnancy or if the breeding dates are not known.ny negative result may indicate that a bitch is not pregnant. However, if the test is performed early in pregnancy, before the placenta is sufficiently developed, then the level of relaxin will be too low to be detected and the test will fail to indicate pregnancy.