Progesterone in Human Subjects

Effects of Oral Progesterone on Three Indexes of Ovulation 

Medication Number of cycles Mean cycle length (days) 

If progestational potency as judged by this assay is an index of fertility-controlling potency, we would seem to have a formidable array of orally active compounds. The especially high potency of two of them (JX and XII) would seem to assure us of especially effective substances. Furthermore, in the rabbit the oral effectiveness of these compounds as ovulation inhibitors roughly parallels the progestational efficiency (Pincus and Merrill, 1959). 

---