Jasmine Mamiya, a mother of two, was shocked to learn she had developed a third breast after giving birth to her second child. While recovering in the hospital, a lactation consultant pointed out what appeared to be a nipple growing under her armpit — something Mamiya initially thought was just a skin tag.
The consultant explained that during pregnancy, it’s possible for some women to grow extra breast tissue along what’s called the “milk line” — a vertical path running from the armpits to the groin. These can sometimes form a full third breast, complete with a nipple, and even have the ability to produce milk.
Mamiya had noticed the area under her arm changing during pregnancy. It became darker and more swollen, much like what happens to normal breast tissue. Although she had breastfed before and felt confident in her knowledge, she wasn’t expecting to be told she’d grown an extra breast.
After showing the third breast on TikTok, her story went viral, gathering millions of views. Many viewers were curious and surprised to learn that this was even possible. Some asked if it could produce milk — Mamiya confirmed that while it might be able to, she had no intention of testing it by pumping her armpit.
She said that the lump becomes swollen and tender if she doesn’t breastfeed regularly, but staying consistent with feeding and using heat and cold helps manage it. While some extra tissue may shrink after pregnancy, Mamiya is considering surgery to remove the third breast after she’s done having children, although the nipple itself can’t be removed as easily.
Despite the unexpected development, Mamiya took it in stride and used her platform to educate others. She referred to the phenomenon humorously and even called it the “sisterhood of the 3rd nipple.” She emphasized the importance of sharing real postpartum experiences, pointing out that many women go through unusual bodily changes after pregnancy — including developing a third breast.