The chances of getting pregnant by ejaculation during sex three days after menstruation are very small, and generally the chances of getting pregnant are greatest when you have sex during ovulation under normal circumstances. The three days after menstruation belong to the follicular phase of the menstrual period, the follicles are in a state of development and not yet mature, so there is no ovulation, and the chances of pregnancy are very small if you have sex before ovulation. However, it should be noted that some women have irregular menstrual periods due to hormonal disorders in their bodies, in which case the three days after menstruation cannot be strictly defined as the follicular phase, and in this abnormal state, although having sex three days after menstruation, there is still a chance of pregnancy. Therefore, it is recommended that women take the corresponding more reliable contraceptive methods to contraception, as far as possible, do not choose the safe period of contraception to contraception, to avoid unintended pregnancy to cause harm to the body.