A woman has gone viral for sharing this little-known pregnancy side effect, where extra breast tissue has formed in her armpits

Pregnancy, while a natural miracle, can also be one big mystery. TikTok has been instrumental in building a community for new mums, as they make a journey that can be full of surprises as their body grows a baby.

One TikTok user has gone viral after sharing a video of a rare pregnancy side effect of hers – lactating from her armpits. The video shows ducts in both armpits, which she describes as “rock hard and painful!”

So what does this side effect mean and what can we do to treat it? Dr Sarah Welsh, gynaecologist and co-founder of sexual and intimate wellness brand Hanx, has given us all the answers.

What is this pregnancy side effect actually called?

Dr Welsh tells GLAMOUR that developing extra breast tissue, or accessory breasts, is a condition called polymastia – this is defined as “abnormal accessory breast tissue found in addition to normal breast tissue”.

How common is polymastia and why do people who are pregnant get it?

“Although pregnancy can bring with it many unusual bodily changes, lactating from your armpits is not a common one,” Dr Welsh says. “Around 1-6% of women are reported to have this, and sometimes this accessory breast tissue can extend into the armpits.

“In some cases, the extra breast tissue can have nipple or areola in it, but if not, it’s often only discovered around pregnancy and childbirth when milk can be expressed from the tissue, and the area can become swollen and painful.”

Can polymastia be prevented or treated?

“If you are concerned you have milk coming from your armpit, it’s important to see a medical professional for review and diagnosis,” Dr Welsh advises. “Polymastia is a congenital condition and is not serious, but it can cause some discomfort during pregnancy.

A congenital condition means that you’re born with it, so polymastia can’t be prevented. That said, the lactation is generally only caused by pregnancy.

In terms of treating polymastia, the more serious or uncomfortable causes may require surgery, but not in all cases.

“Many people do not treat the accessory breast tissue, unless it causes problems such as pain, swelling, aesthetic concern, or cancerous changes,” Dr Welsh says. “If you chose to treat, it is generally recommended to remove the accessory breast tissue through surgical excision, liposuction or both.”

In terms of things you can do to relieve minor discomfort, she also advises taking lengths to relieve any pressure your extra breast tissue may be having on the rest of your body.

“Some women can pump breast milk from the area to relieve this pressure and continue breast-feeding.”