Using a dummy (or pacifier)
About thumb sucking
The question of whether you use a dummy, or allow your baby to suck their fingers or thumb, is a very individual decision and one that really comes down to you and your baby. Babies are born with a very strong, natural urge to suck. This is known as the
sucking reflex, with some babies being born with a greater need to suck than others.
Babies who naturally suck their fists or thumb soon after birth have probably been doing so for many months inside the womb. Studies into how babies grow and develop inside the uterus have shown that they can suck their fingers as early as 15 weeks of the pregnancy, with some babies being born with 'sucking blisters' on their hand, wrist or arm (reflecting how busy they have been sucking away while in utero).
Babies are also born with an instinctual hand-to-mouth reflex (or the 'Babkin reflex'). This means they will place their hands, fingers or thumb into their mouth as a way to calm, soothe and comfort themselves when upset, tired or distressed (or just for something to do). Babies who master this strategy and use it often, tend to be much easier to live with. The medical term used to describe a baby's need to suck for comfort (rather than for hunger) is known as 'non-nutritive' sucking (or 'NNS') or possibly 'comfort sucking'.
Most parents are surprised at how much and often their baby cries (especially in the first 3 to 4 months), with thumbs and dummies being one of the commonest ways for parents to settle their baby and help them to sleep. How you feel about using either, neither (or both) of these options is up to you and your baby's preferences. Some babies will happily take a dummy, while others may gag on it (or literally 'spit the dummy') and prefer their fingers or thumb. Therefore if your preferences are different from your baby's, you will need to teach them to accept a dummy, and possibly continually pull their thumb out of their mouth for a while.