Fetal growth
(Source: Internet)

In the womb

The best place for the unborn baby to be to develop normally and receive appropriate stimulation is the mother’s womb. Since this is where the preterm infant was still supposed to be it will help you to understand the function of the womb environment in order to understand and adapt the behaviour and handling of your premmie.

While the fetus is developing in the womb, different sensory systems develop in a specific sequence. The order of development is first the tactile system, which involves the skin and sensory inputs such as touch, pain and temperature. Next the vestibular and proprioceptive systems, which are responsible for balance and movement and then the gustatory system follows. This system is responsible for the development of taste in the fetus. The olfactory system is responsible for smell and the auditory system for hearing. The final sensory system to develop is the visual system and the neurological system develops throughout pregnancy and continuous after birth. When you understand this sequence it will support you in understanding you premmies reactions, such as startling when there is a loud noise. Following is a brief discussion on the development of each sense.


The sense of touch develops from the head to the toes and is stimulated even before mom knows that she is pregnant. When realising that you are pregnant a mother-to-be will automatically apply deep pressure over her tummy that will stimulate the tactile system in the fetus and sensitize him to positive touch. This further calms the fetus and prepares him for cuddling as calming technique after birth.

The sense of touch develops around the mouth area as early as eight weeks, and at 20 weeks skin receptor cells are in place all over the body. At 24 weeks the fetus already responds to touch of the palm with a weak grasp and at 26 weeks, the palmar grasp reflex will be stronger. The baby will hold onto anything placed in her palm, such as the umbilical cord, when still in utero or dad’s finger after birth.

Grasping during pre-birth operation
(Source: Internet)

Fetus sucking on thumb
(source: Internet)

Movement and Balance

The fetus may also begin to show a stepping response to touch on the foot sole. This is followed by the development of movement and balance during the third month of pregnancy. This sense is perceived through muscle and joint sensations, such as stretching and contraction.

From as early as 7.5 weeks post menstrual age, movement can be observed on an ultrasound. At only 15 weeks gestation, all the different types of movements the infant will need are present, including startles, general movements, hiccups, and breathing. At 10 weeks the fetus can put his hands to his face and turns around in the womb, although these movements are not yet felt by the mother. Yawning as well as sucking and swallowing starts at the 12th week of gestation.

Finger movements also starts at 12 weeks and periods without any detectable movement are very short, only about two minutes per hour. The vestibular (balance) system is functioning well at 25 weeks gestation when the fetus exhibits a ‘righting reflex’. This is when mom changes her position and the baby uses the vestibular system to change his position back to an upright position. Interesting to note that from 10 weeks the right arm moves more than the left, and from 15 weeks the foetus sucks its right thumb more than its left.


The gustatory system (taste) is next to develop.  Taste buds are present from as early as eight weeks and are mature by the end of the first trimester.  This is also when the fetus starts to suck and swallow.  The fetus tastes everything the mother eats, since the taste molecules are absorbed in the amniotic fluid and as the fetus swallows the amniotic fluid, it tastes what the mother tastes.  The unborn baby prefers sweet tastes, since mother’s milk is sweet and this helps with survival when feeding and self-soothing after birth.

First Trimester
(Source: Internet)

Tissue filled nasal cavity
(Source: Internet)


The ability to smell starts around 28 weeks of gestation, although the olfactory neurons develop much earlier.  The olfactory system is very sensitive to both noxious and pleasant stimulis and negative smells may cause negative reactions, such as a change in heart rate and breathing.  For this reason a plug-like tissue fills the nasal cavity between two and six months’ gestation to prevent certain smells from reaching the relevant receptors.  After birth the baby will thus calm with a pleasant smell like such as scent of her parents or a smell mother was exposed to often during the pregnancy such as scented vanilla candles.


The auditory (hearing) system is very sensitive in the fetus and preterm infant.  The fetus responds to sound as early as 16 weeks gestation, although the auditory system is not mature by then and can easily be overstimulated. The fetus can hear by six months gestation, but can only discriminate between different sounds during the third trimester. 

Sounds applied directly (through earphones, etc) to the pregnant mom’s abdomen can be very disturbing and harmful for the unborn baby.  Suitable auditory stimulation for the unborn baby is mom and dad’s voices and normal everyday activity.

Hearing development
(source: Internet)

Fetal development
(Source: Internet)


The last system to mature is the visual system and it starts its development from week four of gestation.  From weeks 24-26 the fetus responds to light, and by week 26 the fetus will start opening its eyelids.  Even though the fetus is able to “see” while it is still in the womb it is only from eight months gestation that the fetus is able to protect its eyes from light (by constricting the iris).  For this reason, babies that are born preterm will definitely need protection from direct lights while in the NICU.


The neurological system develops throughout pregnancy and important structures in this development include the myelin sheath – a fatty layer that act as isolation around the nerves to transport impulses to the brain for interpretation.  Neuronal connections is also formed which help the different systems to communicate with each other. The development of the myelin sheath is not completed in a preterm infant and this may lead to behavioural challenges.

On the other hand the neuronal connections that form during pregnancy are positive in nature, but in preterm birth negative experiences are responsible for these connections, also leading to behavioural challenges.  The fetal brain quadruples in sizes between 26 and 40 weeks of pregnancy, indicating the amount of stimulation and development taking place.

Fetal brain growth
(source: Internet)

Thumb sucking
(Source: Internet)

Reflexes in the womb

Fetal development is an important period for development of skills that are crucial for survival in later live. Some of these skills that develop include reflexes that support self-soothing, like the sucking reflex. Babies learn to suck and swallow while in utero, but the sucking reflex is only developed properly and matures into a coordinated reflex ready for feeding at 36 weeks gestation. This is important to understand when initiation of feeding comes into play.

A natural self-soothing behaviour that already develops in utero is that baby’s hands are brought up to the face and around the mouth.  This “hands-to-face” position helps to calm and comfort the fetus while in utero and this skill becomes even more important after birth and must be supported.

Hands to face
(Source: Internet)

A natural self-soothing behaviour that already develops in utero is that baby’s hands are brought up to the face and around the mouth.  This “hands-to-face” position helps to calm and comfort the fetus while in utero and this skill becomes even more important after birth and must be supported.

Foot-bracing is another important self-regulatory method.  The legs are flexed with the feet on top of each other, but most importantly the soles of the feet are well supported.  This promotes good flexion and support proper muscle development, but also provides a sense of security for the fetus.  The boundary provided by the amniotic sac is a firm, but flexible one and allows the fetus to stretch and explore his environment, and further support his return to a well-flexed position, known as physiological flexion.

Fetal foot bracing
(Source: Internet)

Read more on fetal development and how the fetus experiences his environment in Chapter one of Prematurity – Adjusting your Dream.

*Footnote: To simplify writing and reading, gender is referred to as:  A fetus as his/he, the preterm or newborn infant as her/she and toddlers as his/he.  This does not exclude the other sex.

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