Birth is never routine, no matter how I attend as a pediatrician. To anyone who cares to notice I must appear grumpy on arrival to the maternity unit. Yet an interesting thing happens when I witness another birth, it becomes an up lifting experience.
The work of delivery is an ageless struggle of pain and sweat, aptly called labor. The palpable tension of the delivery room is finally relieved with the arrival of the newborn through the bloody mess of human fluids and ends with cries of joy and exhaustion. A healthy infant usually brings a sigh of relief, not just to mother but to each human in the room, even those who have attended thousands of these highly personal dramas.
On the Women’s Care unit when the new infant is handed off from the Obstetrician into the hands of a trained newborn resuscitator, they often look pale and limp. With a few simple but highly efficient interventions this limp rag doll transforms into a pink crying baby in just minutes. To the untrained eye must look like our team performed some magic; assisting a lifeless baby to take air. In truth the miracle is a sequential change that moves the fetus from a tethered aquatic existence to an terrestrial being in just an evolutionary millisecond. It all happens with rapid internal changes in blood flow, vessel openings, glucose production, thermal regulation and aided by the physics of fluid surface tension. It’s a ballet choreographed with complexity beyond human skills yet one that is usually performed flawlessly.
The engine of the infant was intricately primed to start before birth. Our nurse and doctor teams are very good but we don’t do much more than made sure the oxygen access remains open, feather the throttle and hit the right puff on a kick start and “varoom” this fragile being caught life with a cry that sometimes rivals that of a Harley.
The physiologic design that allows this all to happen is remarkable. As an example, the unborn infant has been blessed with a special type of hemoglobin in their blood cells that carries oxygen with a much stronger affinity that adult hemoglobin. It holds the precious O2 tighter than a child's hand clings to a treat in the cookie jar. With this grasp on oxygen it is this special fetal hemoglobin that makes it possible to deliver impressive levels of oxygen from minimal supply to the fetus. This is one of the many reasons why we hate to see pregnant women smoke; the carbon monoxide from the cigarette bumps off the precious oxygen with ease.
Another adaptation is the mechanical transformation of the head, facilitating by the pressures moving down through a very tight birth canal. The head is designed to adapt to this narrow tight canal with fluid like dynamics and molds to a shape that adapts to the passage. Each of the soft skull bones called fontanels actually fold and change the head from ball to more like a cone. This shape shifting doesn't cause brain damage and quickly remodels round in the days after birth.
Consider the plumbing changes in blood flow and the dramatic rerouting of circulation. That miracle occurs when blood flow detoured before birth is suddenly rerouted to take on oxygen from the infant’s lung, not the placenta. A detour blood vessel, called the Ductus, rapidly closes after birth sends the blood now into the lungs instead of the aorta. This vessel has specialized sensors that are programed close with just a small increase in oxygen. When this occurs the pale infant becomes dramatically pink this change can be observed as the pink color appears first in the chest and face before the abdomen and legs. The Ductus is not the only blood flow plumbing valve at birth. The upper chambers of the fetal heart; called the atrium take in blood from the placental and the newborns lower body. This blood is shunted across an opening called the Foramen Ovale located between each atrium before birth. This flapper valve structure closes when the pressures in the right atrium drop from new flow into the opened pulmonary vessels.
If one is still skeptical of this miracle “golden hour” of birth consider this recently understood difference; oxygenated blood has a higher kinetic flow rate than slower flowing un-oxygenated blood yet both types of blood return to the same anatomic location in the heart. Yet, it is the higher flow blood that preferentially enters the heart and is sent onward to the most important place… the developing brain.
The kick start mentioned earlier is actually not the force of the force of the air but rather triggers an ancient reflex, designed to initiate additional deeper breath and designed to move air all the way into the small alveoli of the lungs. This reflex, remarkably called “the reflex of Head” is effective and is needed overcome the 10 fold initial resistance of lung opening to set up vigorous and repetitive breaths. To help in this task a special soap- like chemical lining the small sacs of lung called “surfactant” comes into play to make breathing effortless by means of increasing the surface tension to keep the bubble open inside the lung sac.
After delivery we put the baby to the mothers chest for warmth, intimate bonding and to imitate breast feeding which helps tighten the uterus on any residual bleeding vessels where the placenta detached. Inherent reflexes again take over in suckling even though real breast milk is still days away. The newborn is ready for that delay as well and comes with 2-3 days of fluid in its tissues. The infant's liver is also a bit of lunch box and stores glycogen, called on to supply glucose delivery as steady fuel source for the brain. These adaptations make it possible for the infant to survive 3 days with minimal calories; the 5-10 % weight loss observed during this time is normal, and not a reason to switch to formula.
When the labor is over bonding occurs thanks to another adaptation; a heightened level infant alertness in those first few hours of life.
My drive home is at slower pace than my trip in. I travel past the blossoming apple orchards and green farm land and can’t help but be in a better mood after witnessing another miracle of birth, it is never boring and it never gets old.
Michael Jordan, MD, MS-HQSM, CPE, FAAP, Chief of Pediatrics at Newark-Wayne Community Hospital is board-certified in Pediatric Medicine. He attended the College of Human Medicine at Michigan State University and completed his residency training at the University of Rochester. In addition to his leadership role as chief of Pediatrics at Newark-Wayne, he is the medical director of Rochester Regional Medical Group and is also chair of Rochester General Medical Group’s Quality Committee. He works in the Sodus Rochester General Medical Group Pediatric office. To send questions on children’s health, please email Wendy Fisher, Pediatric Practice Manager at firstname.lastname@example.org and write “Ask a Doc” in the subject line. To schedule an appointment, call 315-483-3214.
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