Transdermal contraceptive hormones delivery

1. A method of preventing pregnancy in a woman that comprises, during an eight week or a twelve week treatment cycle having a treatment interval of seven weeks or eleven weeks and a rest interval of one week:

(A) transdermally administering a contraceptively effective amount of a progestin and an estrogen during the treatment interval by successive weekly applications of three or seven transdermal hormone delivery treatment interval devices, one for each week of the treatment interval, and

(B) transdermally administering low dose progestin and low dose estrogen throughout the rest interval by application of a low dose transdermal hormone delivery device during the rest interval wherein the rest interval device delivers between 25% and 75% of the amount of progestin and between 25% and 75% of the amount of estrogen as delivered by each treatment interval device;

whereby the woman experiences menstruation during the rest interval;

wherein

the estrogen is selected from one or more of: estradiol-3, 17-diacetate: estradiol-3-acetate; estradiol 17-acetate; estradiol-3, 17- divalerate; estradiol-3-valerate; estradiol-17-valcrate; 3-mono-, 17-mono- and 3,17-dipivilate esters; 3-mono-, 17-mono- and 3,17-dipropionatc esters; 3-mono-, 17-mono- and 3,17-dicyclo pentyl-propionate esters: 3-mono-, 17-mono- and 3,17-dicyprionate esters; 3-mono-, 17-mono- and 3,17-diheptanoate esters; 3-mono-, 17-mono- and 3,17-dibenzoate esters; ethinyl estradiol; and estrone; and

the progestin is selected from one or more of: levonorgestrel; norgestrel; norgestimate; 17-deacetyl norgestimate: desogestrel; gestodene: norethindrone; nore-thynodrel; hydrogesterone; ethynodiol dicetate; hydroxyprogesterone caproate: medroxyprogesterone acetate; norethindrone acetate; progesterone; megestrol acetate; and gestogen.

2. The method of claim 1 , wherein the rest interval device comprises the same progestin and estrogen as the treatment interval devices.

3. The method of claim 1 , wherein the rest interval device has the same hormone concentrations as each treatment interval device but is a fraction of the size of the treatment interval device.

4. The method of claim 1 , wherein the rest interval device is the same size as each treatment interval device but comprises reduced amounts of the estrogen and progestin compared to the treatment interval device.

5. The method of claim 1 , wherein: (a) the amount of progestin delivered during the rest interval is ¼, ⅓, ½, ⅔, or ¾ of the amount delivered from each treatment interval device during the treatment interval; and (b) the amount of estrogen delivered during the rest interval is ¼, ⅓, ½, ⅔, or ¾ of the amount delivered from each treatment interval device during the treatment interval.

6. The method of claim 1 , wherein the rest interval device is worn during all of the rest interval.

7. The method of claim 1 , wherein the estrogen in the treatment interval devices and the rest interval device is ethinyl estradiol.

8. The method of claim 1 , wherein the dosing regimen provides an average of about 15 to about 65 pg/ml of ethinyl estradiol during each treatment interval, in a given woman or in a population of women.

9. A kit for use in the method of claim 1 , comprising:

(a) seven or eleven, or a multiple of seven or eleven, transdermal hormone delivery treatment interval devices, each treatment interval device comprising a progestin and an estrogen in an amount sufficient to reduce the risk of pregnancy, each being intended for wear for one week; and

(b) one rest interval device for each seven or eleven treatment interval devices, intended for wear during a one week rest interval between successive seven-week or eleven-week treatment intervals, wherein the rest interval device comprises: (1) low dose progestin in an amount sufficient to deliver 25% to 75% the amount of the progestin delivered during each week of the treatment interval, and (2) low dose estrogen in an amount sufficient to deliver 25% to 75% the amount of the estrogen delivered during each week of the treatment interval.

10. The kit of claim 9 , wherein the rest interval device comprises the same progestin and estrogen as the treatment interval devices.

11. The kit of claim 9 , wherein the rest interval device has the same hormone concentrations as each treatment interval device but is a fraction of the size of the treatment interval device.

12. The kit of claim 9 , wherein the rest interval device is the same size as each treatment interval device but comprises reduced amounts of estrogen and progestin compared to the treatment interval device.

13. The kit of claim 9 , wherein the treatment interval device and the rest interval device are formulated such that: (a) the amount of progestin delivered during the rest interval is ¼, ⅓, ½, ⅔ or ¾ of the amount delivered from each treatment interval device during the treatment interval; and (b) the amount of estrogen delivered during the rest interval is ¼, ⅓, ½, ⅔ or ¾ of the amount delivered from each treatment interval device during the treatment interval.

14. The kit of claim 9 , wherein the estrogen in the treatment interval devices and the rest interval device is ethinyl estradiol.

15. The kit of claim 9 , in which the treatment interval devices are formulated to deliver an average serum concentration of about 15 to about 65 pg/ml of ethinyl estradiol during each treatment interval, in a given woman or in a population of women.