Africans were also used in large numbers for slavery because they were easier to buy. During the beginning of the Atlantic Slave Trade, Africans were willing to sell other Africans as slaves to Europeans because they had their own system of slavery.
You could have sex towards the end of your bleeding and then actually conceive 4 or 5 days later with your early ovulation. The probabilities of getting pregnant while on your period are low, but the possibilities are there. This is not the time to have sex if you are trying to get pregnant.
No, sex doesnt delay periods if there is no pregnancy but if you are worrying a lot that you might be pregnant then the anxiety, stress and worry might delay your period. Even worrying about exams, family or work problems can delay periods if the worry is big enough. RTS.