Compositions and methods for the delivery of progestin hormones that have binding affinity to the Sex Hormone Binding Globulin (SHBG) are disclosed. The compositions combine such progestins with non-progestin SHBG ligands to displace at least part of the progestin from SHBG in the blood plasma, thereby increasing its bioavailability. Also disclosed are methods to modulate progestin and estrogen levels in the blood through the use of SHBG binding and displacement, to optimize the effectiveness of formulations for contraception and minimize the side effects and adverse events.