For women with regular menstrual cycles, just after menstruation is usually a safe period, but for women with irregular menstrual cycles, just after menstruation is not necessarily a safe period.
Safe period usually refers to a period of time that excludes the menstrual period, the day of ovulation, and the four days before and after the day of ovulation, which is usually 14 days before the next menstrual period. For women with regular menstrual cycles, the safe period is seven days before and eight days after the onset of menstruation. So just after menstruation is within the safe period.
For women with irregular menstrual cycles, unexpected ovulation may occur, so just after menstruation is not necessarily a safe period.
If there is no plan for pregnancy, it is recommended to use safe and effective contraception, and the safe period method of contraception is not safe.