So this question came up yesterday with my boyfriend and me, since I'd had to take a Plan B after a condom malfunction. I know that the hormones in Plan B can throw off your own hormones for a few months afterwards (and did for me the first time I took it), but does anyone know how long the hormones actually stay in your body? Assuming that it is effective in stopping pregnancy for the prior sex in question, wouldn't it technically be effective for preventing pregnancy for a day or so (or maybe longer? I don't know, that's why I'm asking) after taking it? It's more a curiosity than anything else. I have no intention of using Plan B as birth control now or in the future (regular HBC is way cheaper anyway), but I was just wondering. Thanks!