Developing Senses

Touch

7 weeks onwards : sensitive to touch around the mouth.
12 weeks : puts thumb to the mouth to suck.
24 weeks: sensitive to touch all over the body (especially around the mouth). Touching the palm triggers a grasp reflex.
28 Weeks : grasps with toes when touched on the ball of the foot.

 

Taste and Smell

17 weeks : taste buds that detect sweet, salty, bitter and sour and savoury qualities are present.
24 weeks : the infant can detect different flavours in the amniotic fluid.
26-27 weeks : reacts to bitter taste and can detect irritants in odours such as alcohol and perfume.
28-29 weeks : Reacts differently to sweet and sour taste.
34 weeks : prefers sweet taste.

 

Hearing

27 weeks : moves in response to sounds.
28-29 weeks : Starts to distinguish between sounds and voices and is most aware of low frequency sounds. Sleep is easily disturbed.
34 weeks : Starts to recognise familiar sounds and begins to ignore some sounds that previously disturbed sleep.

 

Movement

Preterm infants have very little muscle matter and they need to be held and to have the support of comfortable bedding which helps them to limit big, abrupt and tiring movements. They require sufficient space to push out against the boundaries of their “nest” to build muscle strength.

Moro Reflex: the infant makes startled movements in response to a change in head position, a sudden movement or change in light, sound or temperature. The Moro occurs up to 10 months post term.

Grasp Reflex: When the infants palm is touched he/she closes his/her hand. Grasp reflex is seen from 11 weeks gestation up to 3 months post term. This reflex is associate with sucking.

Rooting: when the infants cheek or corner of the mouth are touched, the infant turns his/her head towards it, opens the mouth and extends the tongue in readiness for sucking.  Rooting may also happen when a baby grasps. Rooting is present from 24 weeks gestation to about 4 months post term.

Asymmetric Tonic Neck Reflex: When the infant’s head is turned, the arm and leg on the face-side straighten out, while the other arm and leg bend. This position encourages kicking and allows the infant to look at his/her hands and be more aware of the surroundings. This reflex is present from 18 weeks gestation to about 6 months post term.

 

Vision

24 weeks :Sensitive to light even when asleep and tightens eyelids when exposed to bright light.
32 weeks : Orientates eyes to a source of sound and may briefly gaze towards a face in very low light.
34 weeks : Starts to look at and track a moving object or face in soft light. Perceives patterns of light and shade but not meaningful objects.
39-40 weeks : Perceives images and requires light to see shapes.

 

Sucking and Swallowing

24/25 weeks : Sucking and rooting reflexes can be elicited.
26 weeks : Baby can gag.
28 weeks : May nuzzle at the breast and lap at the mother’s nipple.
32 weeks : Roots in search of food. May latch on and suck at the breast with short bursts and several sucks per swallow.
37 weeks : Co-ordinated sucking with one suck to one swallow and one breath.