Crinone® (progesterone gel)(also marketed under the brand name prochieve) is a specially formulated vaginal gel that contains the female hormone progesterone. Progesterone helps prepare the lining of the uterus for the arrival and implantation of the embryo. After implantation, progesterone helps maintain the pregnancy until the placenta is able to provide its own hormonal support.

Unlike injectable progesterone, Crinone® is applied into the vagina where it adheres to the vaginal walls to be absorbed directly where it is needed. This route of application avoids the local pain and skin abscesses associated with intramuscular injections of progesterone.

Crinone which is also sold under the brand name Proceheive is a natural form of progesterone, the vaginal gel has one major benefit: Because it is applied through your vagina and goes to your uterus, the progesterone is absorbed right where you need it most.

Crinone (Prochieve) currently the only natural progesterone bio-adhesive gel on the market, was introduced in 1998.

When you take progesterone in pill form, about 95% of it is metabolized and eliminated from your system -- which is why you often need a high dosage. The vaginal gel form, though, is more bioavailable -- that is, it is able to be used by your system more easily, and isn’t metabolized. So you don’t need as high a dosage -- again, cutting back on side effects. Studies conducted by the pharmaceutical company showed that the majority of women didn’t have side effects normally associated with progestins -- and even had fewer than women taking natural micronized progesterone.