Who is at the lowest risk for developing breast cancer?

• A. Nulliparous women
• B. Women who gave birth before 20 years old
• C. Women who have dense breasts
• D. Women who had menopause early

Answer: (B)

Reproductive history shapes breast cancer risk, and an early full-term pregnancy provides long-lasting protection. When a woman carries a pregnancy to term, breast cells differentiate in a way that reduces the number of cells that could become cancerous, and it shortens the period of high estrogen exposure that promotes cell proliferation. Having the first full-term birth before age 20 offers a greater reduction in risk than pregnancies started later or not at all, making it the lowest-risk scenario among the options. Dense breast tissue raises risk because more glandular tissue can undergo malignant changes and also makes detection harder. Early menopause lowers risk by reducing overall estrogen exposure, but the strongest protective effect in this set comes from having a birth before 20.