What are the dosages of birth control pills vs. Plan B?
Many of the birth control pills come in easy-to-use dispensers in which the day of the week or a consecutive number (1, 2, 3, etc.) is written on the dispenser with a corresponding tablet for each day or number.
For example, some Ortho-Novum dispensers are labeled “Sunday” next to the first tablet. Thus, the first tablet is to be taken on the first Sunday after menstruation begins (the first Sunday following the first day of a woman’s period). If her period begins on Sunday, the first tablet should be taken on that day.
For birth control pills that use consecutive numbers, the first tablet (#1) is taken on the first day of the menstrual period (the first day of bleeding). Tablet #2 is taken on the second day and so on.
Still other packages instruct women to begin on day five of the cycle. For such products, women count from day one of their menstrual cycle (day one is the first day of bleeding). On the fifth day, the first tablet is taken. Tablets then are taken daily.
Most birth control pills are packaged as 21-day or 28-day units. For 21-day packages, tablets are taken daily for 21 days. This is followed by a seven-day period during which no birth control pills are taken. Then the cycle repeats.
For the 28-day units, tablets containing medication are taken for 21 consecutive days, followed by a seven-day period during which placebo tablets (containing no medication) are taken.
Newer formulations with 24 days of hormone pills and only four days of placebo pills are now available, as are continuous or extended-cycle oral contraceptive regimens, in which only active hormone pills are taken. Extended-cycle preparations include seven-day intervals of placebo pills to be taken approximately every three months.
Women just starting to take birth control pills should use additional contraception for the first seven days of use because pregnancy may occur during this period.
If women forget to take tablets, pregnancy may result. If a single tablet is forgotten, it should be taken as soon as it is realized that it is forgotten. If more than one tablet is forgotten, the instructions that come with the packaging should be consulted, or a physician or pharmacist should be called.
- Emergency contraception pills should be taken as soon as possible and not more than 72 hours after unprotected sex or when birth control fails.
- Single dose regimen: Take one 1.5 mg tablet as soon as possible within 72 hours of unprotected sex or when birth control fails.
- Two-dose regimen: Take one 0.75 mg tablet as soon as possible within 72 hours of unprotected sex or when birth control fails, followed by a second 0.75 mg tablet 12 hours later.