Very little or no cost Can be used by most couples if they are committed to it. Once learned, there would be no need for professional help Very effective if used correctly and consistently. Can be learned from trained volunteers. Contact with trained medical personnel is not necessary. It is immediately reversible.
Periodic abstinence is acceptable to the religious groups that reject other methods.
No effect on breast milk or breast-feeding. No hormonal side effects. Involves men in family planning. Usually only somewhat effective. Less time to learn the calendar method, although it is best if a woman has records of the last 6-12 cycles to identify the fertile time.