by Dr. Michael Jordan
Birth is never routine, no matter how I am called upon to 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, I can’t stay grumpy because it is never boring and it never gets old. 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 birth canal 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 responds into a pink crying baby in just a matter of minutes. To the untrained, it looks like our team performed a miracle; assisting a lifeless baby to take air, but in truth, the miracle is an incredible sequence of developmental planning that transforms the fetus from a tethered aquatic existence to a 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.
Our nurse and doctor teams are very good, but we don’t do much more than made sure the oxygen access remains opened. The engine of the infant was intricately primed to start before birth, our teams just turned a key, feathered 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. Birth is an orchestrated sequence of interrelated adaptations that make this possible. 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 obstetricians 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.
Another amazing adaptation to life is 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 oxygen sensors that are programed to trigger closure. When this occurs, the pale infant becomes dramatically pink can be visually observed as the pink color happens in the chest and face before the abdomen and legs. This Ductus is not the only blood flow plumbing valve closure 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 between each atrium before birth. This flapper valve structure closes when the pressures in the right atrium drop as blood flows into the new opened pulmonary vessels.
If one is still skeptical of this “golden hour” of birth as miracle should consider this recently understood design; oxygenated blood has a higher kinetic flow rate than slower flowing blood without oxygen returning to the same anatomic location it is the higher flow blood that is preferentially sent 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 ten-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 initiate 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 two to three 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 three days with minimal calories; the five to ten percent weight loss observed during this time is normal, and not a reason to switch to formula. When the labor drama is over, an intense bonding happens thanks to another adaptation of infant alertness in the first few hours.
As the sky becomes light and I drive home, at slower pace than my trip in, I go past the blossoming apple orchards and green farmland and can’t help but be in a better mood after witnessing another miracle of birth.
Michael Jordan, MD, MS-HQSM, CPE, FAAP, Chief of Pediatrics at Newark-Wayne Community Hospital is board-certified in Pediatric Medicine. 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 wendy.fisher@rochestergeneral.org and write “Ask a Doc” in the subject line. To schedule an appointment, call 315-483-3214.
