How to prepare your firstborn for a second baby

The question I kept avoiding was the obvious one: how do you tell a child who has had you completely every morning, every bedtime, every scraped knee and bad dream that someone else is coming? Someone who will need you in ways that are, at least at first, louder and more urgent than anything they need?

There's no clean answer to that. But there is a way to do it that's honest, age-appropriate and kind. And there are ways that make it harder than it needs to be, most of which come from trying to frame the whole thing as purely good news.

Why this transition is harder than we admit

For a firstborn child the arrival of a sibling is genuinely destabilising. Not because something bad is happening but because something that was true about their world stops being true. They had your undivided attention. Now they won't. That's a real loss even inside a family that wanted another child and will love them both.

Child psychologist Adele Faber, whose book Siblings Without Rivalry (1987) remains one of the most influential works on sibling dynamics, described the experience of a new sibling through a memorable analogy: imagine your partner coming home one day and saying, "I love you so much I've decided to get another partner just like you. You'll share everything the house, the attention, the love. Isn't that exciting?"

The absurdity of that scenario, applied to a small child, is worth sitting with. Their reaction regression, clinginess, acting out isn't manipulation. It's a completely rational response to a significant change.

A 2019 study published in the Journal of Child Psychology and Psychiatry found that firstborn children showed measurable increases in behavioural difficulties in the months following a sibling's birth, with effects most pronounced in children under four. The study also found that the quality of parental preparation and ongoing attention significantly moderated those effects. In other words: what you do before and after matters.

When to tell them and what to say

The timing depends on your child's age and how concrete their sense of time is. For toddlers, nine months is abstract to the point of meaninglessness they live in the immediate present, and telling them too early just extends the waiting without adding comfort. For children over three, a few months of preparation tends to work better than either very early or very late disclosure.

What you say matters less than how you say it. A few things that help:

• Use simple, honest language. "A baby is growing in my belly and will come to live with us." Not "you're getting a friend" that's a promise you can't make.
• Let them ask questions and answer them at their level. Some children want details others aren't interested yet. Follow their lead.
• Acknowledge that things will change. Not in a frightening way, but truthfully: "The baby will need a lot of feeding and sleeping at first. Sometimes I'll be busy. And I'll still love you exactly the same."
• Avoid the phrase "you'll always be special." Children hear what isn't said. What they need to hear is that your love for them is not being divided it's expanding.

What preparation actually looks like

Telling them is the beginning, not the whole thing. The months before the baby arrives are useful for building a few things into the family's fabric:

What to build before the baby comes. Why it helps?

One-on-one rituals that are specifically theirs

Gives them something that won't be disrupted

Familiarity with babies in books, videos, real life

Normalises the reality of what a newborn is actually like

Language for big feelings

"I feel left out" is more useful than a tantrum

Small responsibilities around the baby's arrival

Involvement builds investment, not resentment

A trusted person outside the immediate family

Someone they can go to when you're unavailable

That last one is underrated. Knowing that Grandma or a favourite aunt, or a family friend is their person right now not a replacement, but an additional safe adult does a lot of quiet emotional work.

After the baby arrives: the part nobody prepares you for

The preparation is important. What happens in the first weeks after the baby comes is where things can go either way.

Regression is normal. A previously toilet-trained child who suddenly isn't, a four-year-old who wants a bottle, a child who has reverted to baby talk these are not signs of damage. They are signs of a child who is communicating something they don't have words for yet. The response that helps is neither alarm nor irritation, but matter-of-fact warmth: "I know things feel different right now. That makes sense."

Direct expressions of jealousy are actually better than silence. A child who says "I hate the baby" is processing something. A child who goes very quiet and very helpful may be suppressing something. Both need attention but the second is easier to miss.

The guilt that you'll feel as a parent for not being as available to your firstborn as you were, for watching them struggle while you're feeding the baby, for the moments when you simply can't come that guilt is worth naming here. It's almost universal. And it doesn't mean you've done something wrong.

If the emotional complexity of this transition is landing harder than you expected, Emotional exhaustion in motherhood: what it really means speaks to what it feels like when you're carrying too much at once. And if the resentment that sometimes surfaces between you and your partner over who is carrying what has started to have a specific texture, Resentment in motherhood: where it comes from is worth reading.

The thing you need to hear

Your firstborn will be okay. Not immediately not without some difficulty and not because you managed this perfectly. But because children are resilient in ways that tend to surprise us, and because a sibling even one that arrives in chaos and disruption often becomes, over time, one of the most important relationships of their life.

"Siblings are the people we practise on, the people who teach us about fairness and cooperation and kindness and caring quite often the hard way." - Pamela Dugdale

The transition is hard. It's supposed to be hard. That doesn't mean you're failing it.

Further reading: Adele Faber & Elaine Mazlish, Siblings without rivalry (1987). Daniel J. Siegel & Tina Payne Bryson, The whole-brain child (2011). Laura Markham, Peaceful parent, happy siblings (2015).