Infant development in the first three months
Never again does the human develop at the rate it does in the first three months of life. Newborns typically sleep around 16 hours out of 24, conserving energy and allowing for the Active Sleep state, which wires the enormous human brain in advance of each stage of physical and intellectual development. Humans produce a unique milk which supports this rapid brain growth, unlike many mammals who need to produce young with strong muscles and bones to allow them to keep up with a moving herd.
Cow’s milk is “udderly” perfect for fuelling the rapid growth of a calf at-foot of a grazing mother cow.
Most healthy, full-term newborn babies double their birth weight around four months and triple it around their first birthday. By contrast, a baby cow will double their birth weight in around 60 days!
At birth, your new baby is basically a bundle of reflexes, instincts, basic bodily functions and a very immature brain!
The range of vision at birth is around 30cm, just enough to clearly see their mother’s face from the breast or resting on her chest. They can’t always coordinate their eyes together to focus so can sometimes look cross-eyed but they should get the hang of it by around 3 months. Your newborn has immature hearing which responds best to that annoying high pitch we all seem to use when speaking to them! They recognise sounds which are familiar from the womb, like the voice of their mother and others regularly speaking around her. Their sense of taste is very basic at this stage - they can recognise sweetness, which is all they really need as breastmilk is very sweet! And their sense of smell is developed enough to recognise the scent of their own amniotic fluid on their mother’s skin and the smell of her colostrum and breastmilk. Its like a really basic model, enough to get them through the early period after birth - no extras!
It takes time to work out how everything works!
The development of the central nervous system works from the top down. Your baby’s first intentional movements will be lifting their own head and being able to track moving objects with their eyes. Newborns are fascinated by faces and can hold eye contact with others for surprisingly long periods. Their sense of touch is heightened in the areas around the mouth, the palms of their hands and soles of their feet. Skin-to-skin contact is not a passive activity for the baby, their brain is processing even the lightest touch.
The baby’s experience of touch makes a significant leap after the first few weeks of life. As the central nervous system continues development, babies begin to gain control of the arms and hands. They progress from being touched by the people and surfaces they come into contact with, to being someone who touches. The feedback they get from accidentally touching things with their hands drives them to gradually develop the ability to hold and release, to guide and intentionally move things. Around 6 months, these skills become practical as they learn to pick up food in the hand and bring it to their mouth. They will practice and develop these skills by holding simple toys, first grasping them when placed into their hand and later grabbing them when placed in reach.
The initial language of a newborn is very basic: unintentional grunts and sounds and crying. Crying is a broad form of communication which has the sole purpose of signalling to the mother they are needed to provide care. Very experienced parents might be able to associate certain cries with particular needs and some midwives claim they can identify boys from girls by their newborn cries but mostly crying simply increases in urgency the longer the delay. And that can be increments of seconds, not minutes.
Hearing development becomes more refined as the brain develops. Your baby may become still when a new or unexpected sound captures their attention as they try to identify the direction from which it comes. By around 4 months, they can turn their head in the direction of a new sound. Babies seem to enjoy some sounds more than others, including the type of white noise they find soothing. Around six weeks, your baby might smile when you speak to them, as they continue to to learn what makes You you!
Our skin is our biggest organ and newborns are highly sensitive to touch.
Although your baby is many months away from intentional mobility, they are still capable of accidental movement. For this reason, it is never safe to leave a baby unattended on any surface higher than the floor. By three months, you are probably going to see first attempts at leg movements - uncoordinated, clumsy movements which will become what we call kicking. The nervous system has a lot of work ahead before crawling, standing and walking are possible and the foundations are beginning installation. Complex movements will be needed in the second half-year and rolling them out will require significant development. Sleep disruption in the second six months and beyond can be directly related to mobility progression. Be prepared!
Tummy time is promoted as being important in avoiding flat head syndrome, formally known as plagiocephaly. This is particularly of concern in babies who regularly spend long periods “contained” in car seats, baby bouncers, swings and other equipment designed to hold babies when parents cannot. Initially, newborns will retain the foetal-like position when laid on their tummy and many babies do not enjoy the experience. There is no evidence than tummy time must be practiced on the floor, despite parents being told this is the case. Lying tummy down on an awake adult’s chest encourages raising the head and eye contact, engaging the baby far better than a playmat and propped toy. By three months, your baby will be raising their upper body by taking their body weight on outstretched arms, having progressed through stages of gradually extending their reach. Car restraints should be limited to in-car use for transport. Be aware of moving your baby between containers without allowing lots of floor time in their day. Babywearing is an excellent way to engage the same muscles as tummy time for babies who dislike it.
Tummy time is about being on their tummy, not being on the floor!
A healthy, full-term, breastfed infant receives the exact nutrition required for optimal brain development. Parents can provide the stimulation and environment to support the baby during the incredible evolution we see in this first three months of life. Society needs to support parents as they experience this intense period of nurturing.
