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
Progesterone vaginal ring Progesterone vaginal ring Progesterone vaginal ring, also known as progesterone-only vaginal ring, is a form of vaginal ring used for birth control when breastfeeding. Use can begin at four weeks and continue for at least up to a year following childbirth. Failure rates with usual use is about 1.5 per 100 women. It is used within the vagina with one ring lasting three months. The woman is able to place and remove the ring herself. Side effects include vaginal discharge and pain with urination. It does not appear to be associated with serious side effects. With use menstrual periods often