Lower activity for progesterone receptor than gestodene.
References
Larrea, F.; Garcia-Becerra, R.; Lemus, A. E.; Garcia, G. A.; Perez-Palacios, G.; Jackson, K. J.; Coleman, K. M.; Dace, R.; Smith, C. L.; Cooney, A. J., A-ring reduced metabolites of 19-nor synthetic progestins as subtype selective agonists for ER alpha. Endocrinology 2001, 142 (9), 3791-3799.