A few days before Leah Sperry turned a year old, she was discharged from the hospital, a big success for a baby born 28 weeks premature with cystic fibrosis.

One of the biggest factors that kept Leah going, say her mother Heather Sperry and the child's physician, Dr. Sharon Unger, was the breast milk she received through Ontario's human milk bank.

As the holidays approach, breast milk donations usually slow down, says Unger, who specializes in the care of premature or ill newborn infants at Mount Sinai Hospital in Toronto.

But Unger, also the medical director of the Rogers Hixon Ontario Human Milk Bank, says breast-milk donations are crucial all year round for babies born too early, since they aren't developed enough to handle formula or cow's milk.

"Pre-term babies are at really high risk for something called necrotizing enterocolitis (NEC), which is an inflammatory condition of the bowel and it carries a very high morbidity and mortality," said Unger.

"By being able to provide these babies human milk instead of cow's milk, we can really reduce the risk of this NEC." That's because it's easier for their underdeveloped gastro-intestinal tracts to digest and it contains substances that boost premature infants' immune systems.

'Breast milk increases a preemie's chances'

Leah, fortunately, never contracted NEC. She was born in November 2018 weighing only about a pound and had to go straight into the milk bank program.

"We really didn't have a choice," said Sperry. "I took all the medications and tried all the wives' tales and I could not produce enough milk to sustain her."

Heather Sperry spent nearly a year in the hospital after her daughter Leah was born premature. (Rogers Hixon Ontario Human Milk Bank)

About 70 per cent of women with children in the intensive care unit won't be able to produce enough breast milk, says Unger. It's a combination of the child being born too soon, possible sickness, stress and "having to be pump dependent" to extract milk, instead of being able to nurse the infant.

The Rogers Hixon Ontario Human Milk Bank supports 37 Neonatal Intensive Care Units (NICU). Last year, it distributed 6,000 litres from mothers who donated the extra milk they had. Now, they're reminding everyone that more is needed around this time of year.

Donors are rigorously screened

To become a donor, women have to go through a strict vetting process, since their milk will be going to extremely vulnerable babies. There's a blood test, they have to be non-smokers, free of any medications and able to pump at least five litres of milk over about a two-month period.

Once the milk is gathered, Unger says it's pasteurized to eliminate any excess bacteria.

Krysten Lawrence, far right, stands with her daughter, husband and new set of twins. She wasn't aware of the milk bank program before giving birth to her twins. (Rogers Hixon Ontario Human Milk Bank)

Krysten Lawrence became a donor in Ontario after one of her premature twins needed the program in September 2018.

"Our twin daughter was more vulnerable in comparison to our twin son due to her lower birth weight," said Lawrence.

Since the twins were born early, Lawrence initially wasn't able to produce enough milk so her daughter spent nine days in the NICU where she received milk from the Rogers Hixon's bank.

Health Canada warns against buying milk online

Once she brought her children home, she was on a mission to pump enough milk to give back to the program. After a while she was able to produce five litres of milk.

"It really helps increase the likelihood of a baby's survival in the most fragile first moments of their life and I'm forever grateful and thankful for it," said Lawrence.

Some women turn to online groups to buy or donate milk but Unger warns against that.

"You don't know what medications or other things may be in it," said Unger. "It could even be that someone went to the grocery store and is selling cow's milk."

Health Canada has issued a warning against consuming breast milk not obtained through one of the four banks in either B.C., Alberta, Ontario or Quebec.