'Milk brothers' saved by a donation: this is how a nursing mothers' bank works

Raquel became a breast milk donor seven years ago, when her second daughter was born. Her sister, a neonatologist, told her about this practice, which until then had been unknown to her. She tells this newspaper about the "satisfaction" she felt helping newborns in vulnerable situations . So, in July 2024, when her third baby was born , she decided to repeat the experience. Since then, she has dedicated one of her daily feedings, between 120 and 190 ml, to donating milk: "So far, I've helped 125 children."

In her case, she goes to the Puerta de Hierro University Hospital , located in Majadahonda, which, in addition to having regular services such as outpatient clinics, pediatric emergencies, and a neonatal area, has a room with refrigerators that house the donated breast milk .

This is a satellite center of the Aladina-MGU Regional Breast Milk Bank , whose objective is to supply donated milk to all sick or premature newborns in the Community of Madrid who need it, regardless of the hospital in which they are admitted.

This bank is located in the Neonatology Department of the 12 de Octubre Hospital , but La Paz Hospital, the Severo Ochoa Hospital in Leganés, and the Príncipe de Asturias Hospital in Alcalá de Henares, along with Puerta de Hierro, make up this network of support centers . The project was launched in 2002 at the 12 de Octubre Hospital, after a visit by several neonatologists and nurses to a clinic in Denmark that had a donated milk bank.

Babies who benefit

Katherine is 33 years old and became a mother less than a month ago. Her daughter was born prematurely, at 34 weeks pregnant, due to high blood pressure, also known as preeclampsia , which her mother suffered from. “ My breast wasn't ready ,” she confesses. Because of this, the medical team offered her donated milk. “Although we've successfully breastfed, she still needs it because she demands more than I can give her,” she says.

Like Katherine's daughter, 41 other newborns will benefit from the service in 2024. Regarding the new donors accepted at Puerta de Hierro, there were 47 in that same year and their volume of donations contributed to the regional network amounted to more than 258 liters .

Miguel Ángel Marín , a neonatologist at the hospital and head of the milk bank, explains to El Confidencial that the most important thing to become a donor is to be aware of its existence. Therefore, he emphasizes promoting it in health centers in Majadahonda and among mothers who give birth there . Afterward, you should contact the bank via the phone number or email available at this link . "Everyone knows about blood and organ donation, but not this one," he says.

Marín explains that the initial screening is done by telephone because there are definitive exclusion criteria, such as certain infectious diseases , risky sexual relations, current substance use, a history of heroin use , or a significant language barrier, among others. There are also other guidelines that require temporary exclusion, such as an acute infection, chickenpox, cold sores, or mastitis , although the professional clarifies that this does not mean you cannot breastfeed your baby.

Generally speaking, to be eligible to donate milk, you must have been at least two to three weeks postpartum, and your child must be well established as breastfeeding should never be put at risk. "Most women who make it to the next step, the in-person interview , are not rejected," she notes.

At this stage, they are given a more extensive questionnaire about their health and lifestyle , in addition to a blood test to rule out infections such as HIV, hepatitis, Chang's disease , or syphilis . If everything checks out, the woman becomes a donor: "We teach them proper hand hygiene, and they go home with a pump and sterile containers to store their milk."

At home, they will store it in the freezer, preferably in an empty drawer because, according to the neonatologist, "it acquires a lot of odors," and for no more than 15 days. Afterward, the donated milk will be delivered to the Neonatal Unit of Puerta de Hierro Hospital , with free parking for mothers, or it will be picked up directly from the donor's home through the MilkTruck service . This is a Ronald McDonald House van designed to facilitate donation logistics .

At Puerta de Hierro Hospital, there are four refrigerators labeled with different signs: " Breast milk, raw milk, donated milk, and frozen milk from patients admitted to the unit." All of them undergo an exhaustive process of quality control , nutritional content analysis, and pasteurization at the bank's headquarters on October 12.

As stated on their website, sterility is verified by culturing the pasteurized milk . "After taking the sample, it is frozen again, and traceability is maintained from donor to recipient. The milk is handled with maximum hygiene measures and is operated in a laminar flow hood, and its recommended shelf life is three months," they state.

Regarding the length of time a mother donates, it can be weeks, months, or years , until she decides. The hospital emphasizes that, although they prefer frequent and abundant donations , it can be any amount desired. It's worth noting that it's an altruistic process that Marín describes as "a commendable endeavor." What they do give the mothers is a book and a certificate quantifying the number of foster siblings—babies who, without blood kinship, were breastfed by the same woman—who have benefited from the donations. The bank manager also praises the work of his colleagues: "They are nursing assistants with specific training in breastfeeding."

Importance of breastfeeding

Like Raquel, María is also a donor. Years ago, she hadn't even considered becoming a mother, but she began working at the hospital and understood the impact breast milk has on babies. "In March 2025, I became a mother, and breastfeeding became an important issue for me." After two weeks of cracks and "deadly" pain, she successfully reestablished breastfeeding, achieving a high production . For this reason, in August, coinciding with her return from maternity leave, she began the process. "Since I work here, I bring her during my free time. I feel fulfilled ; it's very nice," she says.

María is convinced that her milk is the best for her baby girl : "She hasn't gone bad; she's very healthy." The neonatologist assures that "it's the best way to feed a newborn": "First comes the mother's own milk, then donor milk, and last, by far, formula ." He adds that it's better tolerated, protects sick or premature babies from serious intestinal problems, and reduces the risk of infection.

Specifically, Europe is currently celebrating Breastfeeding Week under the slogan "Prioritizing Breastfeeding: Creating Sustainable Support Systems ." This message seeks to focus attention on the importance of building environments that facilitate breastfeeding , both at the family and community levels. The Spanish Society of Neonatal Nursing (SEEN) affirms that neonatal units and pediatric and neonatal nursing in Spain are fundamental pillars on which to rely to achieve this goal.