What key information should a nurse gather regarding a client interested in using the calendar method of contraception?

Gathering an accurate menstrual cycle diary for the past 6 to 12 months is essential for understanding the client’s menstrual patterns, which is crucial when using the calendar method of contraception. This method relies on tracking the menstrual cycle to identify fertile and non-fertile days, allowing the individual to plan sexual activity accordingly. A well-kept diary would provide insight into the regularity and length of the client’s cycles, helping the nurse determine the most appropriate days for unprotected intercourse and when to avoid it for effective contraception.

This information is directly applicable to the calendar method, as it relies on predicting ovulation based on past cycles. Consistency and pattern recognition in menstruation are critical for the efficacy of this method, making the menstrual diary the most relevant and useful piece of information to gather for its application.