 | Baker’s dozen 2013-06-27 Author: By Susan Brink |
Pregnant women have long pitied the poor elephant with her nearly two-year gestation period. After nine months, there’s hardly a mother alive who isn’t ready to leave pregnancy behind and get on with labor, delivery and childrearing.
But what if we thought of fetal development as taking a full year, rather than the nine months we’ve always counted off the calendar? Recent science makes a convincing case that newborns have more in common with the fetus they so recently were than with the baby they are soon to become. They need a fourth trimester of development to get them ready to make sense of this wonderful, chaotic world.
Baby brain science
Human infants arrive somewhat “half-baked,” with only 25% of their brains developed. Most others in the animal kingdom are born with about half their brain development completed.
Certainly, we know that after nine months in the uterus, emerge they must, and arrive they do. Neuroscience has become adept at studying the tiny-but-interconnected cells of the brain using brain-imaging technology that goes well beyond earlier scientific tools. Today, CT scans, functional MRIs and PET scans can create three-dimensional images of the brain, allowing scientists to analyze its chemical composition, electrical transmissions and blood flow through the brain.
Because of those advances, we now know that when babies are born, they come equipped with all the neurons, or brain cells, they need – but very few of the synapses, or connections, that allow those cells to communicate with each other.
The neurons are the brain’s raw material, and their number is a function of heredity. But that’s hardly enough for all a human being has the potential to do during a lifetime. The remarkably unfinished infant brain immediately gets busy with the work at hand: building the communication networks that will allow for vision, sorting through the din of noise, recognizing words, learning and for responding to love.
And here is where nature and nurture work together in forming the unique personality of each baby: all of this biological activity mingles with the real world of mothers, fathers, sounds, sights, tastes and smells. The environment that welcomes them works with their natural capabilities to fashion each newborn into the unique and irreplaceable baby for whom parents have been waiting.
There’s work to be done
Here is some of the fascinating development that goes on in those first weeks, even as the infant is fussing, crying, waking up the household at all hours and demanding focused, loving attention around the clock:
Sight is the least-developed sense at birth, but newborns see more than we originally thought. A baby seems to be looking at mother’s eyes when feeding, but really, he or she is probably seeking out the edge of mother’s face. Infants are drawn to contrast, and the edge of a face against a contrasting background is a big draw for babies.
They also love looking up through branches of trees at a blue sky. Something as simple as a dark ceiling fan against a white ceiling, because of its contrast, can hold a newborn’s attention. And with every open-eyed examination of the world through limited vision, the brain is busy building neural connections while parts of the eye simultaneously mature, soon allowing for full vision.
Sound is the most highly-developed sense at birth, but infants don’t have the ability to sort through the din and distinguish one sound from another. Imagine hearing a dog bark when you don’t know what a dog is; now imagine the dog barking and the television set blaring while a big sister is throwing a tantrum.
But one sound is recognizable from the moment of birth: the mother’s voice. They’ve heard it before, every day for nine months, and though it’s now less muffled, they’re drawn to the sound of her voice. From the day they’re born, their brains are busy drawing boundaries between sounds, even beginning the work of figuring out where one word ends and another begins – the foundation of language.
Pain As recently as 15 years ago, many physicians believed that infants didn’t feel pain – or if they did, they were incapable of remembering it. Nurses lanced their heels, gave injections and drew blood with no thought of pain control. Physicians even performed surgery on infants without any attempt to alleviate pain.
They had some scientific basis for their belief: infants’ immature nerve fibers are not fully coated with a substance called myelin, which helps nerves communicate. Scientists thought infant brains weren’t ready to send pain signals across nerves – they were wrong. We now know that pain pathways from the central nervous system to the brain are ready to receive and transmit pain signals.
The medical community in some places has been slow to respond, and it was only in 2001 that an international group of pediatricians and pain control experts called for better pain control when treating infants. We now know that breastfeeding an infant – the combination of sugar in the milk and skin-to-skin contact – will help ease the pain of an injection. (For bottle-fed babies, the same skin-to-skin contact with a few drops of sugared water does the trick.) And every physician should be following guidelines outlined by the American Academy of Pediatrics to address pain when an infant undergoes a difficult procedure.
Cry When parents are at their wits’ end because of non-stop crying, they can remind themselves of this: newborn babies have just one tool of communication, their cry, and that tool is also a tool of survival. Without their cry for attention, for comfort, for food, they would die. Parents and other adults instinctively want to help. But what do they do after they’ve made sure, checking with a doctor if need be, that the infant doesn’t have a health problem? Further, what do they do when they’ve emptied their entire bag of infant-calming tricks: diapering, feeding, rocking, singing, swinging, swaddling, bouncing and walking the floor?
The difficult answer is this: they just keep trying; a new position, a ride in the car, a dark room, a lullaby. Newborn infants, through the transitional period of the fourth trimester, are simply not prepared emotionally or biologically to “cry it out.” When a parent hangs in there with a crying baby, the infant is getting this important and loving message: Even when my parents can’t figure out what’s wrong, they’re still going to stick with me.
Even when my crying frustrates and confuses them, they’re there for me.
Your stick-with-them response is quietly forming, within this noisy newborn’s brain, the optimistic brain structures that signal comfort and support through distress. Babies learn that their parents love them enough to try to help, even when comfort takes a long while.
Building blocks
Every interaction a parent or loving caretaker has with an infant during the fourth trimester – smiling, singing, cooing, speaking, feeding, soothing, rocking, walking – is helping to build and enforce brain architecture. Early interactions are, quite literally, helping to form the person your infant will become. The infant is well-equipped to develop under your loving attention. And soon enough, parents will be rewarded with a smile – a smile that tells you love is flowing in both directions.
Susan Brink is a freelance medical writer and author of “The Fourth Trimester: Understanding, Nurturing, and Protecting an Infant Through the First Three Months.”
