It is common for women to bleed during pregnancy. If she was only three weeks along the tissue wouldnt have been that big. If you get hit it wont cause you to miscarry. Unless you are maybe hit in the tummy pretty hard or something very traumatic but Im not too sure about that. If she even thinks she may have miscarried she should contact her doctor right away. You can have two miscarriages and still have healthy pregnancies and babies. Good luck
I actually found out i was pregnant about 3 weeks ago and was so excited about it. Friday sept 21st I started spotting a little bit. I was still bleeding by wednesday so i called and got in for an ultrasound. During the ultrasound the nurse said everything looked fine and i saw the heartbeat and got pictures and everything. I was so happy about it and reassured. The next day i started to cramp and bleed a bit heavier and continued to friday. I called my nurse back and asked if it was normal after a vaginal ultrasound and she said that i should go home from work and lay down, but that it could have been the ultrasound causing it. So i went home. Within about 2 hours I got extreme sharp pains and more bleeding. Almost unbearable pain, so went in for another emergency ultrasound. As i was undressing and emptying my bladder, a gush a blood came out and so did the fetus. I miscarried at the ultrasound place. I was so upset cuz i still had to do the ultrasound and i just had an empty sac. Horsing around isnt the best thing to do, but it shouldn't have caused anything. Unless her miscarriages before were just like they way she is now, tell her not to think badly. She needs to go to the doctor, they're the ones that can tell her.