When a baby is born prematurely their sensory organs are not fully developed and must continue to grow and mature in a foreign world outside the womb. It is important to understand what is happening with your preemie’s senses based on their gestational age, what to expect, and what you can do to help your preemie grow to their fullest potential.
22- 25 weeks
Babies between 22-25 weeks gestation lack muscle tone and can’t flex their limbs just yet. They however do not remain completely still. Preemies at this gestation are used to floating in amniotic fluid and therefore you will see them twitch and flutter from time to time. The nerves and muscles of these preemies are still immature so their movement will be uncoordinated with a trembling and jerking quality. In the NICU, the baby is placed in “nests” or snuggle-ups to try and keep them in a flexed position, which is important for the development of muscle tone and strength.
Sight: Babies at this gestational age will spend most of their time asleep and will never fully wake with eyes open and alert. Since vision is the last of the senses to develop and mature, preemies at this gestational age may actually still have fused eyelids. When they do open, your preemie will be very sensitive to the light and will need protection from the brightness as much as possible. Controlling the physical environment is key. Using incubator covers and keeping lights dim or off will help your preemie adjust to their new visual world.
Touch: Between 22-25 weeks gestation the skin is still very thin, fragile and sensitive to touch. Pain receptors are not fully developed and pathways not completely connected yet, so stroking the skin may be perceived as painful to the preemie. At this gestational age is best to lay a hand on your baby’s back and give firm yet gentle pressure. Your preemie will sense you are there and this can be calming and reassuring.
Hearing: The auditory organs are fully formed at about 20 weeks gestation. At 22-25 weeks gestation your baby can recognize and hear your familiar voice. Your preemie is used to voices being filtered within the womb from the outside world. Sounds can be amplified within the walls of the incubator, so it’s important not to be too loud and startle your preemie, which can be over stimulating to the developing nervous system.
Taste: Premature babies at this gestation have a developed sense of taste. When in utero the baby begins to swallow amniotic fluid around 12 weeks gestation and can begin to taste its sweet, salty, sour components at around 15 weeks gestation. The taste buds are well developed at about 21 weeks gestation. Preemies at this age will not be getting any nutrition by mouth because of their underdeveloped digestive and neurologic system (suck, swallow breathe doesn’t begin to develop until about 33 weeks gestation.) Babies at this gestation can however have mouth care done with breast milk. Breast milk has natural antibodies that can be absorbed through the oral mucosa and it will also help keep the mouth and lips moist and healthy.
Smell: The sense of smell is not completely formed until around 29 weeks gestation. However, the sense of smell has been developing since around 22 weeks gestation when the amniotic fluid moves through the nostrils as the baby begins to practice fetal breathing within the womb. When a baby is born between 22-25 weeks gestation they may not respond noticeably to the smells of their environment but can be sensitive to strong perfumes and colognes, cleaning products, and the smell of cigarette smoke on clothing and hands. It’s important to keep strong scents at bay and to educate friends and family before they come to visit your baby in the NICU.
26 to 29 weeks
Baby’s born between 26- 29 weeks gestation will have movements that are uncoordinated and often unintentional. Muscle tone is not fully developed and they may keep their arms and legs in a flaccid extended position. Movements that you may see look like twitches and flaps. These are normal movements for this gestational age. What you are seeing is what you would be feeling if your baby were still growing inside of you. As the neurological system continues to develop these movements will become more coordinated. By 29 weeks gestation your baby will begin to develop more muscle tone and will be able to flex the thighs at the hips. Keeping your preemie snuggled and in a flexed position will help develop their muscle strength.
Sight: Babies in this gestational range will spend most of their time asleep and will never completely awaken alert with wide eyes. However, your preemie’s eyes may open occasionally if you keep them well protected from the bright lights. Keep in mind that at this gestational age your baby’s eyes may just flicker open slightly before shutting them again. It’s important to remember to give your baby more time for this milestone to develop. Babies between 26-29 weeks gestation cannot focus on any object or person just yet but will perceive light as blotches amongst the darkness. The preemies eyes are very vulnerable to bright and direct light because the retinas do not have a fully formed network of cells just yet. The pupillary reflex (ability to shut out access light) is absent in babies less than 30 weeks gestation and doesn’t completely form until 35 weeks gestation. The eyelids of a preemie between 26-29 weeks gestation are also very thin and give little protection. Controlling the physical environment continues to be key. Using incubator covers and keeping the light low and indirect is essential as the eyes continue to grow and develop.
Touch: Babies between 26-29 weeks gestation are still sensitive to touch as their skin receptors are still developing. This sense is not fully developed until about 35 weeks gestation so touch may still be perceived as painful if it is sudden and forceful. Gentle but firm pressure is still the very best way to show your baby you are present. It is at this stage that positive touch is so important to your preemie. Kangaroo care, holding your baby skin to skin, is a way to show this interaction and can be very healing for both you and your preemie. During kangaroo care your baby’s senses can be fully engaged- hearing your heartbeat and your soft gentle voice, smelling your skin and feeling the warmth of your body, and being contained in an important flexed position are all important and can help grow your preemie like no form of medicine can.
Hearing: Babies between 26-29 weeks gestation are still developing their sense of hearing and can be sensitive to loud over stimulating environmental noise. Your preemie can recognize your voice but may still not respond fully to it. Signs of overstimulation will be shown in the only language the preemie knows- by sneezing, hiccuping, or even dropping the heart rate. As you spend more time with your preemie you will get to know their specific stress signals and be able to respond appropriately to give your preemie the very best environment for growth and development.
Taste: The taste buds of a preemie between 26-29 weeks are well developed. However, they may not be getting fed anything by mouth just yet. (Suck, swallow, breathe is not fully developed until about 33 weeks gestation.) At 28 weeks most preemies enjoy sucking on a pacifier or their finger to relax and comfort themselves. The muscles may not be strong enough to hold the pacifier in for long periods of time but it’s important to have this connection during tube feedings. Practice will help develop the muscles that will later be used to hit this important milestone. Putting a small amount of milk on the end of the pacifier will help your preemie recognize the connection between feeding times and hunger cues and they will be able to taste and smell the sweetness of the milk.
Smell: The sense of smell still being developed in the preemie between 26-29 weeks gestation. Preemies at this age will begin to recognize and respond to the smell of their parents as they do skin to skin care. It’s important to remember that your preemie is still sensitive to strong environmental scents such as perfumes and colognes, cigarette smoke, and disinfectant or cleaning products.
Babies between 30-33 weeks gestation will begin to have more spontaneous movements but will still continue to be uncoordinated and not purposeful. By 31 weeks gestation your preemie will have a fair amount of muscle tone and may be able to flex the legs in an organized state. The neck muscles may be strong enough to lift the head up and move from side to side. Your premature baby may be better coordinated with suck, swallow, and breathe at around 33 weeks gestation. It is at this stage that oral feeding may begin. (Breast or bottle) Remember, that this is a journey and your baby will need lots of practice (and patience from you) to completely master this milestone.
Sight: At this gestational age, the preemies eyesight and retinas are still developing but they can form images. Faces are their favorite form of stimulation. The eyes can now blink and respond to light and to dark. At 30 weeks gestation your preemie can fix on a simple pattern if placed eight to ten inches from the eyes. Your premature baby may not be able to focus for long periods of time but will continue to get visually stronger week by week.
Touch: Babies between 30-33 weeks gestation are still somewhat sensitive to touch, as their skin receptors are not fully formed until 35 weeks gestation. However, your baby will thrive when placed skin to skin. A baby at 30-33 weeks gestation continues to enjoy being swaddled and nesting helps with feelings of security.
Hearing: Although babies between 30-33 weeks can hear your voice, loud noises are often too much for their underdeveloped neurological system and they will startle easily. Continue to speak softly to your baby as your voice is recognizable to your preemie and is a form of comfort. Between 30-33 weeks gestation your baby is beginning to become more in tune with the surrounding and environment. Your preemie will show you outward signs of stress or stabilization in the only language known. When your baby becomes overwhelmed or has had too much activity they may hiccup, sneeze, or even cry- these are physical signs of overstimulation. As you spend more time with your preemie you will get to know which signs are stress signals and which are stabilization cues.
Taste: Babies between 30-33 weeks gestation are approaching a major milestone- feedings by mouth may begin. Your premature baby at 33 weeks may be able to nipple feed but they may need practice and patience as they remember to coordinate sucking swallowing and breathing. Pacifiers continue to be an important practice tool for preemies during this stage.
Smell: The sense of smell is fully formed in the premature baby at 30-33 weeks gestation. The rooting reflex should be present and your preemie may begin to associate the smell of milk with feeding times. Smell cues will alert the preemie when feeding time is approaching and will help stimulate digestion and contribute to the satisfaction and the importance of feeding becoming an enjoyable experience for your baby. Between 30-33 weeks gestation your baby will continue to thrive and grow with the sweet smell of your skin when doing kangaroo care.
34- 36 weeks
Babies between 34-36 weeks gestation should have all the sensory reflexes in place, although still immature. Most premature babies at this stage can coordinate suck, swallow, and breath. Your baby’s movements are still less coordinated than those of a term newborn, since the muscles are still developing along with nerves and motor cortex of the brain. These movements will become smoother everyday as your preemie continues to grow and develop. At 34 weeks gestation you may notice your preemie may still lack proper posture and hold extremities in a frog like position, but by 36 weeks gestation your baby should have increased muscle tone and be able to maintain a flexed position when sleeping. Your preemie may need help with this and may benefit from physical and developmental therapy throughout the NICU stay to achieve this important milestone.
Sight, Touch, Hearing, Taste, and Smell: Babies between 34-36 weeks gestation use all five of their senses to learn about their environments. Their eyesight is still developing and they can form images- Your face and voice are their favorite forms of stimulation. They will begin to wake more often and thrive from touch and familiar sounds. Your preemie may now be able to organize behavior and express likes and dislikes. It is important to remember that even though your baby is growing and may appear to be similar to a full term newborn, they were supposed to spend these last few weeks growing within the womb. Have patience, as your baby needs this time to master the skills necessary to grow and thrive.