Elisabeth Keturah Anderson-Sierra, 29, from Oregon, US, knew when she was pregnant with her firstborn that she wanted to donate her milk, but had no idea at that point how much her body would produce.
After the birth of her second daughter, she was told she had hyper lactation syndrome - an oversupply of breast milk.
To date, she pumps 225oz a day (1.75 gallons), on top of breastfeeding. Overall, she has donated more than 78,000 ounces of breast milk.
As well as donating milk to a milk bank, Anderson-Sierra donates 50% of her milk locally to mothers in need at no cost.
She shared her story on the Breastfeeding Mama Talk Facebook page to educate people about what it really takes to be a milk donor.
“This is my choice and I truly love what I do,” she said. “But I feel the donor’s side is rarely talked about.”
Anderson-Sierra said: “Many mothers want me to just give my milk freely to them when they cannot provide enough, simply because I have so much.
“Yes I do have a lot to give, but I can’t freely feed all the babies.”
She signed up to a milk bank which donates milk to premature babies in need after her first daughter was born.
She is paid one dollar per ounce of milk, the mum wants people to know pumping is expensive. The compensation she gets from donating to the milk bank allows her to donate locally, mother-to-mother, at no cost.
“I have burned through eight pumps,” the mum said. “Pumps are not cheap. I buy milk bags for milk donated locally, I estimate I use 20-40 bags a day depending on how much milk I put in them.
“I need pumping bras for good support and compression, one at each pumping station and I wash them every day or every other day to maintain cleanliness.
“Nipple creams are another expense. I replace my pump parts and bottles approximately every three months or when wear starts to degrade them in order to keep up with donation standards.
“I also have four freezers I use for milk storage until it is donated or shipped out. I pay for the space they take up.”
But the mum said the biggest price she pays in order to donate the milk is her time.
“My time spent washing and sterilising, setup and breakdown to pump, actual pumping, bagging milk, weighing the milk, labelling, laying out to freeze, organising, and storing the milk,” she said.
“This is time away from my family, my kids. I also can’t just take a day off... I can’t even take a pump off.”
Anderson-Sierra said pumping milk has become ingrained in who she is.
“I feel good about being able to help people,” she told PEOPLE. “This is my way of being active in my community and giving back to humanity.
“And so it’s my labour of love.”