Toddler Hitting the New Baby: What to Do About It

Why it happens

The American Academy of Pediatrics describes the mechanism in one sentence: "as a toddler or preschooler, your child may lack the self-control to express anger peacefully. Instead, they may naturally lash out, perhaps hitting or biting in frustration." It adds that occasional outbursts are normal, especially during temper tantrums.

The AAP's picture of a two-year-old fills in the rest: at this age a child "just doesn't have much control over their emotional impulses", and anger and frustration "tend to erupt suddenly in the form of crying, hitting or screaming." A new baby produces a great deal of frustration — less attention, a changed routine, a tired parent, and a permanent object in the middle of the room that everyone else finds delightful.

The NHS lists life changes, including the birth of a new baby, first among the things that affect a child's behaviour, and notes that children "are quick to notice if you're feeling upset or there are problems in the family."

It is also worth remembering that not all of it is aggression. A two-year-old who pats hard, squeezes, kisses forcefully, lies on the baby or tries to pick them up is often being affectionate with a body they cannot yet control. The response is the same either way: supervision.

The first rule

Do not leave them alone together. Not for a phone call, not while you get a nappy from upstairs, not while the baby is on the sofa. This is not because your toddler is dangerous. It is because a child of this age cannot reliably stop themselves, and because a baby cannot move away.

Practically that means the baby is on the floor on a mat with you present, in a cot, or in your arms — not on a raised surface within reach of a toddler. Doors that a toddler cannot open, and a habit of taking the baby with you rather than leaving them, remove most opportunities.

What to do in the moment

The AAP's guidance on aggression is direct about what a toddler can and cannot do. "Control yourself. They can't yet. Remember, young children have little natural self-control. They need you to teach them not to kick, hit, or bite when they are angry, but instead to express their feelings through words."

• Step in physically and calmly. Move between them. Take the hand. Say the rule in three or four words: "gentle hands with the baby".
• Teach the alternative rather than threaten. The AAP advises avoiding threats such as "stop it or else", because "it is always more effective to teach alternative behaviour." Show what gentle looks like, on your arm or on a teddy, then let them try.
• Name the feeling. The HSE's suggested wording is precise: "I know you got angry because you wanted the toy, it's OK to feel angry but it's not OK to hit or kick."
• Keep your own temper. The AAP says one of the best ways to teach appropriate behaviour is to watch your own: "if you express your anger in quiet, peaceful ways, your child probably will follow your example."
• Do not smack. The NHS is unambiguous: smacking "does not have a lasting positive effect", and "children learn by example so, if you hit your child, you're telling them that hitting is OK."
• Move on quickly. The NHS advises moving on to other things you can both enjoy or feel good about as soon as possible.

The AAP allows for time-outs but places them carefully: "use time-outs sparingly. Time-outs should be a last resort." The HSE takes a stronger line for this age, saying time out and the naughty step are strategies to avoid because young children "do not yet have the skills to fully manage their emotions and calm themselves", and that being calm and loving alongside them works better. Two respected services, two positions — a sign the evidence is not strong enough to settle it, and a reason to be sceptical of anyone who says otherwise.

What reduces it over the following weeks

Hitting a sibling is a bid for something, and the reliable fix is to make the bid unnecessary.

• Give attention for gentleness, immediately and specifically. The AAP's rule is that behaviour plus attention equals more behaviour, and that the way to increase good behaviour is to describe it and praise the effort: "good job being gentle with the baby's hand."
• Protect one uninterrupted slot a day. The AAP suggests that just five minutes of play where the child picks the toy and leads goes a long way, especially straight after a separation. It also suggests plenty of brief, loving physical contact through the day.
• Give them a job with the baby. Fetching the nappy, choosing the babygro, singing during a feed. Being useful beats being displaced.
• Do not blame the baby for your unavailability. "In a minute, when I've finished feeding" lands better than "I can't, the baby needs me."
• Protect their things. A shelf or box the baby will never touch matters enormously to a two-year-old.
• Keep routines steady. The HSE lists keeping to a routine and explaining any changes among the things that help a child feel secure.

Some regression is normal alongside this — baby talk, wanting a bottle, new night waking, potty accidents. The AAP describes regressive behaviour as one of the things reasonably tolerated during stress such as the birth of a sibling. It passes faster if it is not made into an issue.

When to ask for help

The AAP suggests contacting a doctor if aggressive behaviour persists beyond a few weeks, if someone is being physically injured, if a child is being excluded from nursery, or if you are worried about your own safety. The NHS says to talk to a health visitor or GP if you are seriously concerned about your child's behaviour. The HSE adds a version many parents need to hear: ask for advice "especially if the behaviour continues and you feel lost", and notes that a GP can help if you are under pressure and would like support with your parenting.

Asking is not an admission that something is wrong with your child. Most of the time the answer is a health visitor confirming that this is ordinary, and helping you set up the week so that it happens less.