If I have had an abortion and then I decide to get on birth control will it affect my chances of conception when I want to get pregnant again?

'No,' but it varies. Tthe generic answer is 'usually no.' One uncomplicated abortion per se is not associated with infertility, but sequelae to abortion(s) can be. Infertility after abortion is usually from adhesion/scarring in the uterine cavity or damage to fallopian tubes. Later gestation abortions and those with significant complications are at particular risk. Good wishes.