The pill doesnt work at all fo 21 days after a miscarrige anyways.
You ARE more fertilr after a miscarrige I got preg in the same week....
One pill wont do anyting, you gotta take them normally but the only Contraception that works for the first 21 dys after a MC is Condoms
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Taking just one birth control pill after sex WILL NOT prevent pregnancy. The hormones take time to get to work in your system. Also, it is possible to get pregnant right after a miscarriage....it all depends on your body. Some women are fertile sooner afterwards than others.
A random pill taken just once will not do anything, if that's the question. If you missed just one and remembered that same day, then chances of getting pregnant are very low, esp. if it's the first week of pills in the package. And yes, some women have reported ovulating very soon after a miscarriage, so I guess it does happen sometimes.