rhythm method 
noun
A method of avoiding conception favoured by the Roman Catholic Church, by which sexual intercourse is restricted to the times of a woman’s menstrual cycle when ovulation is least likely to occur.Popes Pius XI and XII went much further, allowing couples to take means to avoid procreation: the rhythm method or natural family planning....
- By now, I take it, the rhythm method of contraception must have passed out of favour.
- Many of Dr Jonas' female patients were Catholics, practising the rhythm method of contraception.
- colour circle
- colour-coated
- colour code
- colour commentary
- colour commentator
- colour-conscious
- colour consciousness
- colour constancy
- colour contrast
- colour-coordinate
- colour-coordinated
- colour-coordinating
- colour coordination
- colour-correct
- colour-corrected
- colour correction
- colour cup
- colour-defective
- colour-de-roy
- colour diagram
- colour difference
- colour disc
- colour discrimination
- colour doctor
- colour duster