by abstaining from coitus from day 10-17 of the menstrual cycle
by having coitus at the time of day break
by a premature ejaculation during coitus
Solution
One of the legal method of birth contorl is periodic in which couple abstain from coitus from day 10 to 17 of the menstrual cycle. Abortion by taking medicine is not a legal method. A day break coitus may increase the changes of contraception.