After Ivana Micic's prematurely born daughter was fed by milk from other mums during the baby's stay at a Belgrade hospital, she decided to return the favour to other parents in need.
Ms Micic is now one of a growing number of donors to Serbia's new human breast milk bank, which is also hoping to boost rates of breastfeeding in a country where worryingly few mothers take it up.
"I have become a donor to express my gratitude. As long as I have milk I will donate it," said Ms Micic.
The milk bank at the Institute for Neonatology in Belgrade is a first not only for Serbia but also for the Balkans.
For now it provides breast milk for mostly premature newborns hospitalised there, but it plans to branch out, said Slavica Simic, the head of the department.
"Our goal is to extend the bank in order to be able to feed all prematurely born children, as well as to offer milk to maternity hospitals, surgery departments and even out-of-hospital mothers who cannot breast-feed their babies due to health problems," said Ms Simic.
At the moment the milk bank's donors are mostly mothers whose babies are in hospital and have a surplus, remarked Ms Simic.
During the first year, the bank collected some 2,300 litres of breast milk which made up around one-third of the overall need for the Institute alone, she said.
Another young mother, 26-year-old Ana, said she had "such a good feeling being able to provide milk for other babies, rather than only mine".
"It makes you feel so human," Ana, who did not give her last name, said.
Ms Simic says there is also a woman from the Serbian town of Loznica, some 140 kilometres southwest of Belgrade, who "has been bringing milk to the bank for over a year". But the new milk bank faces an uphill struggle to get donors as Serbia has very low levels of breastfeeding, to the dismay of medical experts and parenting organisations.
The level of breastfeeding is low overall in southeastern Europe, with an average of only 27 per cent of exclusively breastfed children in the first six months, among the lowest in the world according to Unicef figures.
But in Serbia it is even lower, with only 15 per cent of mothers exclusively breast-feeding their babies in this age group, according to the United Nations Children's Fund.
These figures have remained unchanged for years despite laws adopted in 2005 banning the advertising or offering of milk or other food and drinks for newborns "that replace a natural way of feeding".
"It is widely believed that baby formula has been promoted so much that mothers chose it as an easier solution; they were even being advised to do so by some paediatricians," said Aleksandra Jovic, the Unicef official in charge of Serbia's Baby Friendly programme.
Dragana Socanin of the Serbian Parents Network said that a lack of information and support for breastfeeding mothers contributes to the low rate.
"Serbia doesn't have a single booklet or any literature on breastfeeding," she said, adding that the visiting nurses who help new mums often don't have enough time to give proper breastfeeding advice.
"Women are ashamed of breastfeeding in public. Cafés and restaurants are not baby friendly," Ms Socanin said.
To boost the numbers, the Institute for Neonathology is now planning a vast media campaign to promote the breast-feeding and donation of human milk.
"We plan to make our flyers available everywhere women can see them: from high school counselling centres, gynaecologists' practices, maternity hospitals," added Ms Simic.
There will soon even be a vehicle to collect milk from donors in Belgrade, she said.
"Mothers will be able to call us and we will come to check if they can donate, to provide necessary education and collect milk," Ms Simic said, referring to the conditions donors have to meet.
The milk bank rules state that donors must be non-smokers who do not drink more than two units of alcohol a day and are free of sexually transmitted diseases.