Chlordiazepoxide is actually progesterone, which is the hormone progesterone, and chlordiazepoxide is a progesterone gel that tends to be used in patients who are experiencing a more significant reaction to the medication after taking oral progesterone. The medication is made into a gel, which is inserted directly into the woman’s vagina for vaginal absorption, and after it is absorbed, it replenishes the body’s levels of progesterone, which reduces the contraction sensitivity of the pregnant uterus and inhibits uterine contractions, therefore promoting the growth of the embryo as well as the development of the fetus inside the uterine cavity. Progesterone also facilitates the implantation of a fertilized egg, and therefore chlordiazepoxide is often used for fertility preservation therapy, except that it is administered vaginally to avoid gastrointestinal reactions to progesterone.