Final answer:
Premenopausal women should perform breast self-examination about a week after their menses ends, as the breasts are least likely to be swollen or tender, facilitating the detection of any abnormalities.
Step-by-step explanation:
The best time for premenopausal women to perform breast self-examination is about a week after menses ends, option 4. Performing breast self-examinations is crucial because it can help women detect early signs of breast cancer, which is vital for better treatment outcomes. Young women, including teens, should also practice regular self-examinations to understand what is normal for their breasts and to detect any unusual changes early on.
It is recommended to do the examination at this time because the breasts are less likely to be swollen or tender, making it easier to feel for any unusual lumps or abnormalities. Additionally, the consistency of the exam timing relative to the menstrual cycle helps in noticing any changes that might occur from month to month.