Some UK parents who struggled to afford infant formula reported diluting feeds, reusing prepared formula and introducing solid foods earlier than recommended, according to a study examining how rising prices are affecting families.
The research documents serious concerns about infant nutrition, food safety and parental wellbeing. However, the 281 participants were recruited because they were already experiencing financial difficulty, so the percentages should not be treated as estimates for all parents who use formula in the United Kingdom.
The mixed-methods study, published in Maternal & Child Nutrition, combined survey responses with interviews about formula affordability, feeding decisions, household finances and emotional wellbeing.
Nearly 40% of participants reported at least one feeding practice that could compromise infant nutrition or safety. These included watering down formula, reusing leftover formula and reducing sterilization.
Nearly half reported introducing solid foods before their baby was ready or switching to a less expensive milk intended for older babies. Some parents described doing so reluctantly because they believed they had no affordable alternative.
Infant formula is nutritionally designed to support babies who are not breastfed or are only partly breastfed. It must be prepared using the correct ratio of water to powder.
Adding extra water lowers the amount of energy and nutrients a baby receives in each feeding. In severe cases, it can also disrupt the balance of water and electrolytes in the body.
Prepared formula can also support bacterial growth. Reusing milk left in a bottle after a feeding can expose a baby to bacteria transferred from the mouth, while reducing cleaning or sterilization may add other risks.
The study did not directly observe parents preparing feeds or assess infants for health effects. The behaviors were self-reported, and the research cannot establish how often they occurred or whether they caused illness.
Still, the findings show how financial strain can influence decisions about a food that families may have little ability to reduce or replace.
“Infant formula prices were high before the cost-of-living crisis, and rose up to 45% between 2021 and 2023,” said lead author Amy Brown, a professor of public health at Swansea University. “This is a significant issue because infant formula is not a discretionary product.”
Parents also reported making sacrifices elsewhere in the household. About 37% said they had left their homes unheated, 43% had fallen behind on bills and 47% had taken on debt they considered difficult to repay.
Among mothers in the study, 21% reported returning to work earlier than planned because of financial pressure. About 10% of all participating parents said they had taken formula from a store without paying.
These figures describe the experiences of the study group, not national rates. Families facing formula insecurity may also be dealing with broader food insecurity, low wages, high housing costs, limited child care and other financial pressures that the study could not fully separate.
The emotional effects were also substantial. Nearly all participants reported that formula costs had affected their mental wellbeing, with parents describing anxiety, guilt, shame and isolation.
One participant said, “Sometimes I regret having this baby and I feel awful about having those thoughts because I love her so much but I'm not a good mum to her.”
The quote reflects severe distress, but the study did not establish that formula prices caused a diagnosed mental health condition. Researchers relied on parents’ descriptions of how the financial pressure affected them.
Some mothers said they had wanted to breastfeed but did not receive enough support to continue. When they later struggled to afford formula, they described feeling that they had failed twice.
Those experiences point to gaps in infant-feeding support, but they should not be interpreted as evidence that breastfeeding is possible or appropriate for every family.
Parents may use formula for medical, practical or personal reasons. Some supplement breastfeeding, some cannot produce enough milk and some choose formula feeding. Once a baby needs formula, reliable access to an adequate supply is essential.
“We urgently need more holistic support across infant feeding that both ensures more women who want to breastfeed can do so, and those who are using formula have reliable access to affordable products that put babies and parents first,” Brown said.
The study took place in the United Kingdom, where formula pricing, labeling rules, public benefits and health services differ from those in the United States. The findings should not be treated as a direct measure of formula insecurity among American families.
The broader issue, however, is not unique to one country. Infant food insecurity can develop whenever families lack reliable access to enough appropriate formula and begin cutting portions, changing preparation or substituting unsuitable products.
The research also highlights the difference between price and nutritional adequacy. Infant formulas legally sold for the same age group must meet nutritional standards, even when prices vary substantially by brand.
A lower-priced regulated infant formula is not necessarily nutritionally inferior to a premium product. Brand reputation, packaging and marketing can influence purchasing decisions even when products must meet the same basic compositional requirements.
Parents should not switch to toddler drinks, follow-on products or other milks intended for older children without guidance. Products marketed for different ages are not automatically appropriate substitutes for infant formula.
Families having difficulty affording formula may benefit from speaking with a pediatrician, health visitor, social worker or local food assistance organization before attempting to stretch supplies. Feeding changes should be made with professional guidance whenever possible.
The study’s authors have professional and volunteer ties to organizations involved in breastfeeding support, human milk banking, infant nutrition and food insecurity. Those roles may provide relevant expertise, but they are also important context when interpreting a study that discusses breastfeeding support and formula access.
The researchers did not argue that formula-feeding parents should be blamed for unsafe practices. Their findings instead suggest that when an essential infant food becomes unaffordable, some families make decisions they already understand may carry risks.
The study cannot determine how widespread formula insecurity is across the United Kingdom. Larger, nationally representative research would be needed to estimate how many families are affected and which forms of financial or feeding support are most effective.
The study was funded by the UK Medical Research Council. Brown and another author volunteer with the Human Milk Foundation. Other authors reported leadership, trustee, advisory or volunteer roles with First Steps Nutrition Trust, the Independent Food Aid Network, Leicester Mammas, La Leche League Great Britain, the Medics Lactation community and the Hospital Infant Feeding Network.