Pharmacokinetics of progesterone concentrations was around 4 hours and the elimination half-life was in the range of 30 to 40 hours. The venous blood levels observed were very low. Because progesterone is a lipophilic and hydrophobic compound, it is not absorbed efficiently by the skin. Moreover, because the body produces about 25 mg progesterone per day on average during the luteal phase, around 50% of the body would need to be used as a surface of absorption to deliver a similar quantity of progesterone. As such, the transdermal route cannot easily achieve adequate circulating progesterone levels, and this makes transdermal progesterone impractical for
Menstrual cycle continue to secrete progesterone to maintain the new pregnancy. Most pregnancy tests look for the presence of hCG. The uterine cycle has three phases: menses, proliferative, secretory. Menstruation (also called menstrual bleeding, menses, catamenia or a period) is the first phase of the uterine cycle. The flow of menses normally serves as a sign that a woman has not become pregnant. (However, this cannot be taken as certainty, as a number of factors can cause bleeding during pregnancy; some factors are specific to early pregnancy, and some can cause heavy flow.) "Eumenorrhea" denotes normal, regular menstruation that lasts for a