Why babies suck on things

The American Academy of Pediatrics starts from biology rather than opinion: "All babies are born with the need to suck. This is important because babies need the sucking reflex to eat and drink." Sucking that is not for food — on a dummy, a thumb, fingers or a fist — is comfort sucking, and for many babies it is genuinely regulating rather than a habit to be broken.

A dummy at sleep is recommended, not merely permitted

This is the part that surprises people. The AAP's guidance is active: "Offer a pacifier at nap time and bedtime. This helps to reduce the risk of sudden infant death syndrome (SIDS)."

The NHS says the same thing in gentler language. Among its list of things to do to reduce the risk of SIDS: "think about using a dummy to settle your baby to sleep – some research suggests this can help lower the risk of SIDS."

The dummy is one item on a list, not a substitute for the rest of it. The NHS's other points still apply in full: always on the back to sleep, in the feet-to-foot position; a separate cot or Moses basket in your room for at least the first six months; a firm, flat mattress; nothing in the cot that could cover the face; a room between 16C and 20C; no smoking around your baby; and never sleeping on a sofa or in an armchair with them.

If you are breastfeeding

The AAP advises timing: "If you are breastfeeding, wait until breastfeeding is going well before offering a pacifier. This usually takes about 3 to 4 weeks."

The safety rules

Never tie it to anything. The AAP: "Never tie a pacifier to your child's crib or around your child's neck or hand. This is very dangerous and could cause serious injury or even death." The NHS gives the same warning about teething rings, for the same reason.
Check the size. The AAP: "The shield should be at least 1½ inches across so a baby cannot put the entire pacifier into their mouth." The shield should be firm plastic with ventilation holes.
Replace them. "Remember that pacifiers fall apart over time... Do not keep pacifiers past that time." Check regularly for splits and discolouration and throw them out.
Never improvise one. The AAP warns against using a bottle teat and ring as a dummy — the teat can pop out of the ring and choke a baby.
Nothing sweet. The NHS is direct: "If your child uses a dummy, do not dip it in anything sweet, such as sugar or jam." Sugar in prolonged contact with teeth is the main driver of decay.
Do not clean it in your own mouth. This spreads bacteria between you and your baby.

The dental clock

The AAP sets the threshold clearly: "If your child sucks strongly on a pacifier or his thumb or fingers beyond 2 to 4 years of age, this behavior may affect the shape of their mouth or how their teeth are lining up."

The reassurance alongside it matters just as much: if a child stops before their permanent front teeth come in, "there's a good chance their bite will correct itself".

Two qualifiers do the real work in that sentence. Strongly — gentle, occasional sucking carries less risk than vigorous, constant sucking. And beyond two to four years — nothing about the first year of dummy use is on the wrong side of that line.

Thumbs are the harder version

A dummy can be left at home. A thumb travels. That is the practical difference, and it means thumb and finger sucking usually needs to be outgrown rather than removed, which takes longer and is less within anyone's control.

Looking after the teeth either way

The NHS says to start brushing "as soon as their first milk tooth breaks through", using a baby toothbrush and a tiny smear of fluoride toothpaste — a smear up to three years, a pea-sized amount from three to six. Brush at least twice a day, including just before bed, and encourage spitting rather than rinsing so the fluoride stays put. Register your baby with a dentist when teeth start coming through; NHS dental treatment for children is free. And at bedtime or during the night, the NHS says to give only breast milk, formula or cooled boiled water.

Giving it up

The AAP's approach is not confrontational: praise, rewards, distraction, and avoiding harsh punishment. It notes that "most children stop their sucking habits before they get very far in school".

Practically, that tends to mean narrowing where the dummy is allowed before removing it entirely — cot only, then sleep only — and pairing the change with something a child gains rather than only something they lose. Doing it during an already unsettled period, such as a house move, a new sibling or a run of illness, makes it harder for everyone.

What is not typical

Speak to someone if your baby cannot settle at all without constant sucking and wakes repeatedly to have a dummy replaced; if a dummy is being used in place of feeds rather than between them; if you notice changes to the shape of the palate or the position of the front teeth; or if a strong sucking habit is still going vigorously as the permanent teeth approach.

When to speak to a health visitor or doctor

Raise it at the routine reviews — the NHS's two-year review covers tooth brushing and going to the dentist explicitly, and dummy use fits naturally there. Contact your health visiting team, GP or dentist sooner if feeding is being affected, if you are worried about tooth or jaw development, or if you want help stopping and previous attempts have not worked. A dentist is the right person for the dental question; a health visitor is the right person for the settling one.

Dummies and Thumb Sucking