Swollen genitals and enlarged breast tissue are common for newborn boys and girls. This swelling and redness is caused by the rush of the hormone estrogen, which is passed from mother to baby before birth. These estrogen levels start to lower soon after baby is born. A baby girl’s swelling will decrease in a couple of weeks, but a baby boy’s swelling may take a few weeks to a few months before it goes away. It’s also common for girls to have a mucous discharge with streaks of blood from the vagina up to one week after birth. Both newborn girls and boys may have lumps of tissue beneath their nipples, or their nipples might excrete a small amount of milky fluid. This milky fluid will stop and the breast tissue will shrink on its own during the first few weeks.