My Sister has been having sex with her boyfriend for almost 18 months. She uses birth control pills (skips one now and then, only 17) and he uses condoms. About 2 weeks ago, after they had sex, she started gushing blood and "chunks." It lasted for 3 days and lessened each day till almost nothing on day 3. I've had a miscarriage myself and it happened just about the same way. Could it have been?

It's possible... however, was she near the time of her period? Sometimes sex either soon before or right after may result in more bleeding. Had she missed a period? Are her cycles regular? Has she ever experienced any mid-cycle bleeding while on the pill?