Progesterone, which regulates cyclical changes in the endometrium of the uterus and maintains a pregnancy The letters α and β[18] denote absolute stereochemistry at chiral centers—a specific nomenclature distinct from the R/S convention[19] of organic chemistry to denote absolute configuration of functional groups, known bey Cahn–Ingold–Prelog priority rules. The R/S https://www.metooo.es/u/672d0f1bd5e0d01190f7f4a1