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Medical Health Encyclopedia
Birth Control Options for Women - Oral Contraception
(Page 3)
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Desogestrel is the progestrin used in Mircette. Approved in 1998, Mircette was the first oral contraceptive to offer a low estrogen dose and a new type of dosing regimen. Some studies suggest an increased risk for blood clots with desogesterel.
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Drospirenone is used in Yasmin and Yaz. (Yaz contains a lower dose of estrogen than Yasmin.) Because drospirenone increases blood levels of potassium, women should not use Yasmin or Yaz if they have kidney, liver, or adrenal diseases.
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Levonorgestrel is used in Seasonale and Seasonique, as well as many other oral and non-oral contraceptives.
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Norethindrone is used in Loestrin and Loestrin 24 Fe (which adds iron supplements to the placebo pills).
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Norgestrel is used in various generic and brand contraceptives.

Types of Regimens. Combination pills are sold in 21-day or 28-day packs:
- Each pill in a 21-day pack contains estrogen and progestin. Women take 1 pill a day for 21 days, and then wait 7 days before starting a new 21-day pack.
- 28-day packs typically start with 21 hormone pills and add 7 placebo pills that do not contain hormones. After taking hormone pills for 21 days, a woman takes the inactive pills for 7 days. Some newer brands, like Yaz, use 24 days of active pills and 4 days of inactive pills. Mircette uses 21 days of low-dose progestin and estrogen, followed by 2 placebo days, and then 5 days of very low-dose estrogen. Loestrin 24 Fe uses 24 days of active pills followed by 4 days of iron-containing placebo pills.
Oral contraceptives may be taken in cycles that include pills of the same or different strengths. These are categorized as monophasic (one-phase), biphasic (two-phase), or triphasic (three-phase). (In 2010, the FDA approved the first “four-phasic” birth control pill, Natazia.) Monophasic pills contain the same amount of hormones in each dose and deliver the same amount of estrogen and progestin every day. Biphasic, triphasic, and four-phasic pills contain different dosages of hormones within the pill packs and deliver different amounts of progestin and estrogen at two, three, or four times within the 28-day cycle.
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