How do I move from breast milk to formula?

Slow for her, slow for you

For her, it's a new taste, a new consistency and a different way of digesting. Nappies change — firmer, darker, often less frequent — and that's expected rather than a problem.

For whoever is breastfeeding or pumping, dropping feeds suddenly leaves the breasts overfull, which is uncomfortable and carries a real risk of blocked ducts and mastitis. Supply comes down gradually if you let it, and painfully if you don't.

The main reason we introduced formula was simple: Mama was not producing enough milk. The days were long and the nights were even longer. Milk supply rises and falls with how often milk is removed, but exhaustion does not care about a pumping schedule. Miss a session because you desperately need sleep, or have a baby who is not sucking effectively, and supply can drop. It can come back, but that takes work. Stilltee tea, breast massage and hot or cold compresses helped Mama feel more comfortable, but regular milk removal was the part that mattered most for supply.

So the pace serves both of them. Replace one feed, hold there for several days, then replace another. Two to three weeks is comfortable. Faster is possible but you'll feel it.

Which feed to start with

A mid-morning or early afternoon one, where nobody is desperate and there's time for it to go badly.

Not the night feed, and not the one she's most attached to. Those go last.

We kept breast milk and formula in separate bottles. It made it easier to see how much of each she had taken, and it meant precious breast milk was not wasted if she stopped early.

It also often works better when someone other than the breastfeeding parent offers the first bottles. Being held by the person who normally breastfeeds you and being offered something else is a hard sell. Papa offered more of the early formula bottles because Ari did not smell him and immediately think, ooh, breast milk.

Watch for two things

The nappies, because they will change and you need to know that's normal rather than assume something has gone wrong. There's a whole separate guide on the constipation that often follows.

And genuine allergy signs, which are different from a bit of unsettledness — a rash, swelling, breathing changes, forceful vomiting, or blood in the nappy. Those are a call rather than a wait.

If she was premature, or there's a family history of allergy, have the conversation with your doctor before you start rather than after.