Transdermal Birth Control
Jessica, at feministing, has an update on spray-on (metered-dose transdermal spray, or MDTS) birth control.
Here's a good review of transdermal birth control methods:
Patch (Ortho Evra)
Description: Patches, sprays, or gels, applied weekly or daily, that transfer hormones through the skin.
Stage of development: One product marketed.
Effectiveness: Patches—0.8 to 1.3 pregnancies per 100 women in the first year as typically used.
How they work: Patches release estrogen and progestin through the skin, preventing ovulation, thickening the cervical mucus, and suppressing endometrial growth.
What’s new? Patches require attention just once a week. Used correctly at higher rates than combined OCs. Sprays or gels transfer fast-drying progestins onto the skin. They are absorbed immediately and diffuse into the bloodstream.