Once an embryo is implanted, progesterone acts to maintain the pregnancy. Crinone is a bioadhesive gel containing micronized progesterone. The pharmacokinetics of progesterone from Crinone gel are rate-limited by absorption. Absorption is prolonged, due to the bioadhesive and sustained-release properties of the gel. The bioavailability of progesterone from Crinone vaginal gel is comparable to that of a progesterone vaginal capsule, but is more than 20 times higher than that of a progesterone oral capsule.
Most women respond to once-daily therapy.
If pregnancy occurs, treatment may be continued for up to 10-12 weeks. Progesterone has not been proven beneficial in preventing miscarriage in women with a history of recurrent spontaneous abortion.