A nurse is providing client teaching about the basal body temperature method of birth control. Which of the following information should the nurse include in the teaching?

A. This choice is incorrect because the body temperature does not drop 1 degree 1 week after ovulation. The body temperature rises slightly (about 0.4 to 0.8 degrees Fahrenheit) after ovulation and remains elevated until the next menstrual period. B. This choice is incorrect because the body temperature should be taken each morning before getting out of bed or doing any activity. Taking the temperature in the evening can result in inaccurate readings due to variations in daily activities, meals, stress, exercise, etc. C. This choice is correct because the body temperature might decrease slightly (about 0.2 degrees Fahrenheit) just prior to ovulation due to a surge in estrogen levels. This dip in temperature can indicate that ovulation is about to occur and that the client should avoid unprotected intercourse if she wants to prevent pregnancy. D. This choice is incorrect because the body temperature is not at its highest during menstruation. The body temperature drops at the onset of menstruation due to a decline in progesterone levels and marks the beginning of a new cycle.