Elisabeth Anderson-Sierra has been called a super producer, a pumping queen and even a milk goddess. But this Oregon mother of two calls herself something a little more humble: “I’m a mom with a gift.”

Her ability is producing and pumping vast quantities of breastmilk that she donates to help babies in need. Since February 2015, she’s donated more than 78,000 ounces — that’s 609 gallons — of breastmilk, and has nursed her two daughters.

Elisabeth Anderson-Sierra and her husband, David Sierra, with their daughters, Sophia, 6 months, and Isabella, 2. Steffi K Photography

“I think that everybody should, in order to have that sense of community, be active in their community,” Anderson-Sierra, 29, told TODAY. “This is what I do. This is the gift I’ve been given. This is the gift that I can share.”

Anderson-Sierra’s desire to help save lives goes back to her time in the Coast Guard, when she was trained in search and rescue, and as a longtime blood donor. When she became pregnant and had to stop donating blood, she researched breastmilk donation.

“I had no idea how my body would react,” she said. “I had the mindset that I wanted to do it. Even if I just had one ounce extra a day, I was going to donate it.”

After her first daughter, Isabella, was born in late December 2014, Anderson-Sierra nursed, and she pumped to try to increase her supply so she could donate. Her milk, she said, “seemed to be almost doubling every other day” and she had an oversupply.

She froze the extra milk, and by February 2015, had two freezers full of milk. Anderson-Sierra began donating it directly to families in her Beaverton, Oregon, area. (She has bimonthly blood tests and can provide the results as her milk is not screened.)

A look inside a full-size freezer full of breastmilk that Elisabeth Anderson-Sierra has in her garage. It's one of her four freezers she uses to store breastmilk for donation. Elisabeth Anderson-Sierra

Anderson-Sierra realized how expensive it had become to maintain her hospital-grade pumps and to run the pumps and four freezers. “I was paying to feed other people’s babies, which I didn’t mind, but it was starting to add up,” she said.

So she began donating to Tiny Treasures Milk Bank, which supplies breastmilk to make products for premature babies in neonatal intensive care units.

Anderson-Sierra receives storage bags and is reimbursed $1 an ounce for qualified milk donated to the milk bank, taxable income she says goes right back into her pumping efforts. She says she’s breaking even, or even losing money.

Since she began donating more than two years ago, Anderson-Sierra been sending half her surplus to the milk bank, and half to local families free of charge.

“I do what I do to give back to my community and to save the lives of babies that would have a higher mortality rate without breastmilk,” she said.

After she had Isabella, the highest volume of milk she produced a day was 168 ounces. Now, since her daughter Sophia was born 6 months ago, she’s been pumping an average of 225 ounces a day.

Elisabeth Anderson-Sierra's daughters sitting in front of the first cooler being sent for micropreemies after her younger daughter, Sophia, was born. Elisabeth Anderson-Sierra

Earlier this year, she saw her doctor to make sure her overproduction was not linked to a health problem, perhaps with her thyroid or pituitary gland. “I was found to be completely normal and I just have hyperlactation syndrome,” she said.

Hyperlactation, or an oversupply of breastmilk, is when a someone produces excessive amounts of breastmilk, more than their baby would need, said Dr. Lori Feldman-Winter, a pediatrician and breastfeeding expert. There’s no agreed upon amount that defines the condition, she added.

A breastfeeding mom to a 6-month-old baby would typically produce just under 1 liter a day, or around 25 to 30 ounces, she said.

The amount of milk that Anderson-Sierra is producing is very uncommon, even for people who have hyperlactation. “That definitely is out of the range of the garden variety of hyperlactation we would see,” Feldman-Winter said.

More commonly, women with hyperlactation have a little extra milk. Instead of producing 23 or 27 ounces, they would produce 33 to 40 ounces, she said.

For someone making as much milk as Anderson-Sierra, Feldman-Winter recommends a workup to check for underlying medical problems related to the oversupply.

She would also want to make sure the baby is getting an adequate amount of fat from the breastmilk, which is important for growth. With hyperlactation, breastmilk often has more carbohydrates and less fat, which can lead to slow weight gain, Feldman-Winter said. Or babies could gain too much weight from an overload of carbohydrates.

Anderson-Sierra says she loves being a donor, but it’s not easy. She pumps five times a day, which takes a total of four to five hours, plus time packaging the milk and sterilizing her equipment.

The sterilizers that Elisabeth Anderson-Sierra uses in her efforts to donate large quantities of breastmilk. Elisabeth Anderson-Sierra

“What I do now is very hard, that’s why I definitely classify it as a labor of love,” she said. “There are no slow days. I can never take a day off.”

Anderson-Sierra is driven by hearing success stories of breastmilk helping vulnerable babies thrive, especially preemies.

“I would imagine it feels the same for somebody that donates a kidney, that same feeling that you have just given somebody else a second chance at life,” Anderson-Sierra said. “But I only have one kidney and I have lots of breastmilk to give.”

Noting that breastmilk can save the lives of preemies, who have a greater risk of dying from certain conditions, Feldman-Winter applauded her efforts.

“It is an extremely generous act that she’s made that commitment,” Feldman-Winter said. “And as long as the milk is processed and analyzed, it can be useful for so many babies, particularly those most vulnerable, the babies in the NICU.”

TODAY.com contributor Lisa A. Flam is a news and lifestyles reporter in New York. Follow her on Twitter and Facebook.