Feb 26, · Pregnancy can also cause breasts to be swollen, sore, and tender. In addition, both PMS and pregnancy can cause the nipples to be more sensitive. However, breast pain and soreness from pregnancy Author: Danielle Dresden. Sep 29, · “Pregnancy hormones like estrogen and progesterone are responsible for breast tenderness,” says Kimberly Langdon, M.D., an OB/GYN based in Columbus, Ohio. “As the breasts prepare for milk production, there’s rapid growth happening: blood flow increases, blood vessels expand, cells multiply and breast .