The withdrawal and calendar methods are not considered highly effective and should not be relied upon as primary methods of contraception.
The withdrawal method requires a lot of self-control and timing to be effective which can be difficult to achieve.
The calendar method heavily relies on accurate tracking of menstrual cycles and ovulation. However, human error can occur in recording cycle lengths and sometimes women may have irregular menstruation cycle due to some health factors.
Proper use of modern contraceptives such as IUDs or birth control pills is the best option.
