"Cannot" covers a lot of ground: a body that does not make enough milk, a baby who cannot latch, a medication you need, a return to work with nowhere to pump, or a mental health situation where breastfeeding is not sustainable. All of them are real. This page is about what they have in common and what comes after.
About 60% of US mothers who stop breastfeeding stop earlier than they intended [1]. The reasons most strongly linked to stopping early were problems with lactation itself, concern that the baby was not getting enough or not gaining weight, the mother's own illness or need for medication, and the effort of pumping [1]. Nationally, 86% of babies born in 2023 were breastfed at some point, but only 30% were still exclusively breastfed at six months [2].
So the population of people for whom breastfeeding "did not work" is not small or unusual. It is most parents, to some degree.
The American Academy of Pediatrics' 2022 policy statement lists the situations in which breastfeeding is not advised — a short list including certain maternal infections and some drugs and substances — and separately acknowledges that "exclusive or any breastfeeding is not always possible, despite the best of intentions" [4]. Conditions that limit milk production, such as insufficient glandular tissue, previous breast surgery, or some hormonal conditions, do not appear on a contraindication list but can make exclusive breastfeeding physically impossible. If you suspect one of these, an IBCLC (International Board Certified Lactation Consultant) can assess supply properly, and your paediatrician can check the baby's growth.
Latch problems, tongue-tie, severe pain, mastitis, prematurity, twins, exhaustion, a job without pumping breaks, and postnatal depression or anxiety all sit here. Some are fixable with the right support and time; some are not, or not in the time you have. Only you can weigh that.
Infant formula. For a healthy term baby whose mother's milk is not available, formula is the standard alternative and the one the AAP's statement points to [4]. It is regulated, nutritionally complete for the first year, and the choice most families in this situation make. See our formula feeding guide.
Pasteurised donor human milk. The AAP recommends it for very low birth weight infants when the mother's milk is not available [4]. For healthy term babies, milk-bank donor milk is sometimes available but is usually prioritised for hospital use.
Milk from individuals or the internet. The FDA "does not recommend feeding your baby breast milk acquired directly from individuals or through the Internet", because the donor is unlikely to have been screened for infections, medications or substances and the milk may be contaminated [5]. The AAP notes the same infectious and contamination risks with informal sharing [4]. If you consider any human milk not from your own body, the FDA's advice is to use only a source that screens its donors and takes other safety precautions, after talking to your healthcare provider [5].
If you can produce some milk, you do not have to choose between exclusive breastfeeding and none. Any breastfeeding alongside formula is combination feeding, and it keeps whatever benefits your milk provides in your baby's diet. See combination feeding.
Among 890 mothers using formula in any amount, 67% reported guilt and 68% reported feeling stigmatised, and 76% felt they had to defend their feeding choice [3]. The study's authors concluded that infant-feeding messaging, not the mothers, was the problem. If that is where you are, breastfeeding guilt is written for you.
There is no clean number for 'cannot'. What is measured is that about 60% of US mothers who stop do so earlier than they wanted, and only 30% of babies are exclusively breastfed at six months. Physical inability is one cause among several.
The AAP's policy statement lists a small number of true contraindications, including certain maternal infections and some medications and substance use; insufficient glandular tissue and previous breast surgery can also limit supply. Your paediatrician or an IBCLC can tell you which applies to you.
Infant formula is the standard, safe alternative and is what the AAP recommends when a mother's milk is unavailable for a healthy term baby. Pasteurised donor milk from a screened milk bank is used mainly for very low birth weight infants. The FDA advises against milk obtained from individuals or the internet.