If you are starting HBC for the first time, then it takes 7 days of active pills (on nearly all combined HBC pills) to hypnotize your ovaries into not ovulating. If you start on the first day of your natural period, then those 7 days overlap with days when the ovaries are least likely to ovulate, so you can consider yourself protected from the first pill.
If you are just changing brands, however, you go by the 21/7 rule. 21 or more days of active pills, and 7 or fewer days without them, and your ovarian-hypnosis protection is maintained. (The withdrawal bleed is triggered by a drop in hormones, but while your uterus is bleeding, your ovaries are waking up. This is why missing pills around your no-hormone week can be a bit risky, if you have really gung-ho ovaries that wake up fast.)
So the pharmacist was first giving you "am not currently on HBC" instructions, then switched to "just changing brands" instructions.
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Date: 2011-11-04 03:27 am (UTC)If you are starting HBC for the first time, then it takes 7 days of active pills (on nearly all combined HBC pills) to hypnotize your ovaries into not ovulating. If you start on the first day of your natural period, then those 7 days overlap with days when the ovaries are least likely to ovulate, so you can consider yourself protected from the first pill.
If you are just changing brands, however, you go by the 21/7 rule. 21 or more days of active pills, and 7 or fewer days without them, and your ovarian-hypnosis protection is maintained. (The withdrawal bleed is triggered by a drop in hormones, but while your uterus is bleeding, your ovaries are waking up. This is why missing pills around your no-hormone week can be a bit risky, if you have really gung-ho ovaries that wake up fast.)
So the pharmacist was first giving you "am not currently on HBC" instructions, then switched to "just changing brands" instructions.