Between February 2008 and September 2013 Amelia Boomker, 36, pumped the equivalent of 4,000 baby bottles – nearly 132 gallons. (Or, as one paper helpfully pointed out, the equivalent of 618 Venti size Starbucks.)
After each of her pregnancies Amelia would pump between eight and 10 times a day for about 20 minutes each time and then donate the milk to the Indiana Mothers' Milk Bank in the States.
Ironically, Amerlia was never able to naturally breastfeed her own children and would use bottles instead.
Her oldest son Danny, aged nine, was born with a heart condition and had to be tube-fed.
Liam, six, had a high-arched palate in his mouth which prevented his from latching on to the nipple and four-year-old Ryan, four, never took to breastfeeding.
Meanwhile Connor, who is 18 months old, was only able to do it for a few weeks.
But Amelia said she's proud she's been able produce plenty of milk for her own children and in others need.
She told Today.com: "We joke that there was probably a wet nurse somewhere in the family tree."
The Indiana Mothers' Milk Bank approves around 500 mothers for donation every year.
A spokesperson said: "Our goal is for our moms to be pumping in a healthy manner. So it's not as though we encourage moms to pump an excess amount of milk to go for something like the world record.
"It just so happens that Amelia - she has some pumping skills... it's just insane."
After the breast milk is donated it is pasteurised and dispensed according to guidelines established by the Human Milk Banking Association of North America.
Amelia hopes setting a record will encourage more donors to come forward.
The previous Guinness World Record holders for breast milk donation were Karen Merheb of Dallas, Texas, who gave 14,243fl oz and Alicia Richman of Granbury, Texas, who donated 11,115fl oz.
Amelia said: "I hope that the record continues to get beaten because frankly that means much more milk is getting donated."