Relaxin is a polypeptide hormone that is secreted by the corpus luteum, into the circulation during the menstrual cycle and throughout pregnancy. During the cycle, it stimulates blood vessel growth in the endometrial lining of the uterus during the midluteal phase, coincident with the temporal window during which embryonic implantation occurs. If conception occurs, Relaxin levels rise and remain relatively constant during the entire gestational period (Ref.1). Relaxin is best known for its connective tissue remodelling effects on the female reproductive system. It has diverse actions in the reproductive tract and other tissues during pregnancy. These actions include promotion of growth and dilation of the cervix, growth and quiescence of the uterus, growth and development of the mammary gland and [...]