Is a woman sinful for hitting her abdomen with the washing machine door, and did that stop the fetus's heartbeat, and is the blood that comes down after a miscarriage considered nifas (postpartum bleeding) requiring her to make up prayers if it is not?

You bear no sin for the miscarriage that occurred if you did not intentionally strike your abdomen. If the pregnancy was aborted and no human features were discernible (a minimum of 81 days), then the bleeding is considered irregular bleeding (dam fasad), and you must make up the prayers you missed. However, if human features were discernible, then the bleeding is considered post-natal bleeding (dam nifas), and you are not required to make up the prayers. If the miscarriage was after 12 weeks (84 days) and it was discernible as a fetus, then the bleeding is post-natal bleeding, and the fact that growth stopped in the sixth week does not matter as long as the heartbeat was continuous.