Twenty Babies: An Unexpectedly Quick Introduction to Vaginal Birth
I delivered twenty babies in the summer of 1977. I was hardly more than a baby myself, just turned twenty-four and starting my third year of medical school. At that point I was toying with the idea of becoming a family practitioner or a general surgeon. Babies didn’t much figure into my future.
This is how my obstetrics rotation was supposed to work: a medical student was typically paired with an intern, who in turn was under the direct supervision of a senior resident. The senior resident did the complicated cases—forceps deliveries, cesarean sections, and such—while the intern handled the routine vaginal births. My role as a medical student was more or less like Cinderella’s in her pre-princess days: do the dirty work, like IV starts and blood draws, and stay in the shadows to avoid the wrath of the overworked intern and resident. A “good” student—one with the sense to do his work quietly while openly admiring the skills of his elders—could expect the chance to deliver an uncomplicated baby or two as his reward.
Two things conspired to make this particular rotation different. The first was that it was early July, a traditionally scary time to have a baby in a large teaching hospital, since the interns are only a week out of medical school and generally have less experience delivering babies than the women whose babies they’re delivering. The second thing was that, for reasons I can’t recall, the OB resident staff was a few bodies short of a full complement. This meant that the interns and residents had to cover many more patients than usual, which didn’t leave them much time for supervising green medical students embarking on their first hospital rotation.
And so one sweltering Chicago morning I stood in my crinkly white coat before Mitch, a stocky, gruff senior resident with a startled head of jet-black hair and a permanent dusting of cigarette ash down the front of his scrubs. We were in the hallway outside the maternity ward. Gurneys with moaning women aboard rattled by like Model Ts on an assembly line, pushed by a corps of tough-looking nurses. Mitch had paused between a C-section and a vaginal birth to give me my orders: I was to join Ben, a brand-new intern from a tony private medical school, on what Mitch called the “firing line”—a row of wheeled labor beds separated by unadorned canvas curtains.
Mitch clamped his hand on my upper arm like a bailiff leading a felon into court and marched me through the labor room’s swinging doors to Bed 4, where a tiny nurse with Popeyesque forearms was helping a hugely pregnant woman out of a wheelchair.
“Okay, you had some OB training in your physical assessment class, right?” Mitch asked. No, I told him, I hadn’t. My physical assessment class had been at the veterans’ hospital down the street. There, I had watched men with terminal lung cancer chain-smoke cigarettes through their tracheostomy tubes, had seen others who had lost limbs to diabetes or D-Day land mines, and had personally examined what a senior resident described as the case of the year—a cabdriver who got scurvy (scurvy!) from a decades-long diet of plain White Castle hamburgers and Coke, period. Not only had I not seen a baby born at the VA, I told Mitch, I hadn’t seen a single female patient. The woman climbing onto the bed in front of us would be the first woman I had ever touched with medical intent.
Mitch scratched the stubble on his cheek. “Well, you’ve read about childbirth, haven’t you?” I said that I had. Just the night before, in fact: half a chapter, with diagrams. Took me twenty minutes.
“No problem, then.” He slapped me on the back. “Just sit there”—he motioned me to a rolling stool between the woman’s now propped-up legs—”and call me when you see a head.” Then he left.
I sat there for two hours. I killed time by rearranging the contents of my pockets, cleaning my stethoscope, and, once I had overcome my shyness, talking to the woman who was to produce the head I had been ordered to be on the lookout for.
Her name was Tonya. She was two months younger than I was, and in between contractions I learned that for the last five years she’d been a secretary at an insurance company downtown. This was her third child—her oldest, a girl, was just two and a half—and she absolutely hated childbirth. She compared the pain of having a baby to the pain of being stabbed, which she had been, twice—both times being cases of mistaken identity, she assured me. But childbirth was worse, she said, because “it’s like they won’t take the knife out.” Childbirth and knifing: two experiences I had never had. I took Tonya’s word for it.
Our conversation gave way to long stretches of silence as Tonya’s labor intensified. She panted as her contractions came, her hands gripping the metal siderails of the bed with such force that I thought she’d bend them. Between contractions she stroked her belly with her hands, her eyes closed.
Ben, the intern, came and went in a sweaty blur, muttering to himself as he lurched up and down the row of beds. He shook my hand on one pass. “Everything okay here?” he asked in a strangled voice. “Good,” he said absently, not waiting for an answer. He patted my shoulder and scuttled out the labor room door. I went back to my pockets, moving my reflex hammer, tuning fork, pens, and alcohol wipes from one side to the other and back again while I waited for something to happen.
A sudden eruption of curses drew my attention. Startled, I looked down between Tonya’s legs and saw the top of a tiny head peeking out from her vagina. I shouted for Mitch and then Ben, but neither responded. The nurse who’d been working the firing line was gone, too—off helping them, I supposed.
A pale student nurse appeared behind her clipboard at the foot of Tonya’s bed. “I think they’re doing an operation,” she said. Her eyes widened at the sight of Tonya’s baby’s head. “Maybe I should go look for them?” She dropped her clipboard in my lap and took off at a half-trot. The double doors swung shut behind her. Now it was just me, the swearing Tonya, and the top third of a birthing baby’s head.
I remembered a picture in my night-before’s reading where the obstetrician has his hand placed confidently on the emerging newborn’s head. So I did that. I put my gloved right hand on Tonya’s baby’s head. It was warm and wet, and squishier than I had imagined it would be. Contact made, I exhaled for the first time in what seemed like an eternity.
My relief was short-lived. I had mastered the art of placing my hand on a birthing baby’s head, but what came next? Would the baby just kind of fall out of Tonya on its own, I wondered, or was I supposed to grab on to that puckered patch of scalp and pull? I silently cursed myself for not finishing the chapter. Caught between pulling and not pulling, I chose a middle, temporizing route. Like the Dutch boy at the dike, I put my hand on the baby’s head and pushed back, hoping to persuade it to pause just long enough for Mitch or Ben to come and save me.
Tonya’s curses were getting personal now. She had finished damning her absent husband for putting her through this agony not once, not twice, but three times, and now she turned her attention to me. “Get that damn baby out of me!” she shrieked, glaring at me over the top of her belly. “Get it out now or I’ll cut you!”
Dutch boy be damned. I was losing the battle. There was now an entire head under my hand, face and all. Amniotic fluid bubbled from its nose. Its mouth opened and closed in some horrible parody of breathing. Caught between threats of mayhem and my feeble attempt to hold back eons of childbirthing evolution, I closed my eyes and surrendered myself to whatever came next.
Suddenly a pair of hands pushed me aside. Mitch reached in, grabbed the baby’s head and yanked with so much force that I was afraid he was going to tear it off. He pulled the head sharply downward—the right shoulder appeared at the top of the birth canal—then up, and the left shoulder popped out from below. The rest of the body followed, like a rabbit pulled from a magician’s hat. Mitch plopped the baby in my lap—a big, squalling, slippery boy—and then clamped the cord with a pair of long hemostats and cut it in two. A minute later he tugged on the remnant of the umbilical cord and out came the placenta.
A nurse wrapped the baby in a white receiving blanket and handed him to Tonya, who cried and smiled and cootchie-cooed her thirdborn, seeming to have forgotten for the moment about killing me. His name was Robert, she said, because he had his grandfather’s cleft chin.
“That wasn’t so hard now, was it?” said Mitch, as he jotted a note on Tonya’s chart. I didn’t answer him—couldn’t, really. I just sat on the stool with my mouth hanging open, dumbstruck. My scrub shirt was soaked in sweat. There was blood on my socks and shoes. Mitch stripped off his gloves and tossed them in a trash can at the foot of Tonya’s bed. He yanked me into the hall, where two more mothers-to-be in wheelchairs waited. “Okay, then,” he announced. “Time for the next one.”
Had I been a little more observant—and less panicked—I would have noticed that Robert’s head had rotated one way as I held it, and then back again as his body emerged. I would have pondered the pushing, pulling, and pain of having a baby, and the torpedoish shape of the baby’s head as he lay in my lap. I would have marveled at Tonya’s rapid transition from swearing attempted murderess to doting new mother, and at her ability to ignore the gaping wound in her vagina, the one that Mitch came back to sew up after he’d moved me on down the line to watch for another head. What I had witnessed, had I had the time to process what I had seen, was a highly compressed history of the last several million years of human evolution.
••• One would think, given eons of evolutionary tinkering, that Homo sapiens could have come up with an easier way to birth its babies. What’s the point of putting mother and child through such a painful, risky ordeal? Why aren’t we more like other species, most of whom get the business of reproduction over with quickly and easily? Why can’t we just spawn like salmon, lay eggs like chickens, or bud like yeast? More to the point, why can’t we give birth the way gorillas do?
The female gorilla is a study in childbirthing efficiency. When labor begins, she simply ambles off to the edge of her group and has her baby in a half hour or so, with few visible signs of discomfort. She does this without help; the other members of her group usually ignore her. Compared to a human birth, which lasts an average of eighteen painful hours the first time around and almost always requires assistance from those nearby, gorillas have it easy. If Tonya had been born a gorilla, I think she would have preferred childbirth to getting stabbed.
Gorilla birth is made relatively easy by a fact of obstetrical anatomy: mom is big, fetus is small. Because the female pelvis is so roomy compared to the fetus that must pass through it, birth is a straightforward process. The gorilla fetus starts and finishes labor in the same position—head down and facing forward, toward its mother’s abdominal wall. No twists or turns, no shifting orientation as it negotiates its exit. Just down, down and out.
Human childbirth, though, is more like an Olympic bobsled run. There are two participants with well-defined roles: a mother who does the pushing and a fetus who steers the course. There’s a well-marked start and finish, and in between there are banked turns and the real possibility of disaster. Down at the finish line there’s a throng of cheering supporters, some of them ready to assist when things get tricky, others simply milling around with cameras and champagne.
Childbirth isn’t exactly like a bobsled run, of course. There are no helmets or spandex racing suits, for one thing, and it’s usually not snowing on the participants. Childbirth is also a bit slower. A bobsled in midrace can reach 70 miles per hour. A fetus at its zippiest hits a top speed of roughly .00000025 mph. Of course, that’s only in a woman’s first labor; things can go twice as fast in subsequent deliveries.
Obstetricians divide childbirth into three stages. In the first stage, the cervix, which, along with the vagina, makes up the soft tissues of the birth canal, thins and dilates. The second stage, officially known as the expulsion of the fetus, is the birth itself. The delivery of the placenta constitutes the third and final stage. The second stage is the most prolonged and painful, and the course the fetus travels is, compared to the straightforward path taken by its gorilla cousin, an oddly curvy one.
The human female pelvis is an anatomical puzzle. The birth canal of the gorilla is more or less a compressed cylinder, like a cardboard toilet paper roll with its sides gently squeezed. From top to bottom, the roll is uniformly widest in the front-to-back dimension. The modern human birth canal, though, puts a twist on this ancient design. The upper third of the birth canal in humans is widest in the side-to-side dimension, while the lower two-thirds is widest from front to back, like the gorilla’s. It’s as if our ancestors took the gorilla’s gently squeezed toilet paper roll and, over much time, pinched the upper third sideways, so that the top and bottom of the birth canal are now perpendicular to one another. This is the winding road the human fetus must navigate to get out—a tricky route that leads to a world of childbirthing woes.
Like the gorilla, a typical human fetus spends its third trimester in a head-down position, chin tucked on chest, arms and legs crossed, waiting for the signal to start its run to daylight. But here the differences begin: unlike the gorilla fetus, which faces forward, toward its mother’s abdomen, the human fetus faces backward, toward its mother’s spine. When labor begins, instead of simply dropping into the soft tissues of the birth canal as the gorilla does, the human fetus turns its head sharply to the side, as though making an over-the-shoulder check of the competition. The sideways-facing head then enters the pelvic inlet—the opening of the bony pelvis, the framework of bones that surrounds the cervix and vagina—and, spurred on by uterine contractions, begins its descent. On its way to being born, the fetus flexes, extends, and rotates its body, executing a complex series of maneuvers not seen in any other primate.
Why is human birth so filled with twists and turns? Every other large primate, from baboons to chimpanzees and bonobos, has its babies like the gorilla: a straight shot from womb to world. If human birth is a torturously slow bobsled run, the rest of our large-primate cousins are on a rope-straight downhill ski race. Why are we so different?
Until the mid-twentieth century, the only attempts to explain human birth’s difficulty were framed in theological terms: the commonly held (and, as we’ll see in a later chapter, scripturally questionable) view that childbirth pain was visited upon millennia of women in divine retribution for Eve’s temptation of Adam. But as archaeologists discovered more and more fossilized human ancestors, they learned that the path to painful childbirth was not so much a divine curse as it was a complex compromise between what we once were and what we’ve since become.
Millions of years ago, all large primates gave birth pretty much the way gorillas do today. The maternal pelvis was big enough to allow a small-brained fetus to pass through with relatively little difficulty. But as the ancestors of modern humans split away from the rest of the primate kingdom, childbirth started to get complicated.
The split came about when our distant ancestors came down from the trees and moved out onto the grassy central African savannah. It was a smart move—the savannah offered vast new opportunities for food and water, far from the competing bands of treebound primates who would become today’s monkeys and apes. But it also brought new dangers. The grasses were tall; the tree-swinging, knuckle-walking style of locomotion that worked so well in the jungle now limited visibility, leaving our forerunners vulnerable to the big-toothed predators that patrolled the savannah.
So they stood up. Bipedal (two-legged) locomotion offered the distinct advantage of allowing prehumans to see over the grass, making it easier to spot distant food sources and approaching dangers. Over much time, natural selection for upright walking changed the shape of the skeleton, particularly the pelvis. “Lucy,” the famous Australopithecus skeleton found in Kenya’s Olduvai Gorge in 1974, shows that by three million years ago those changes were well under way. Her pelvis was wider than an ape’s, and her pelvic inlet had already taken on the oval, sideways-oriented shape characteristic of a modern human female.
But Lucy wasn’t completely modern. Much of her pelvis was still apelike, and with Australopithecus being a small-brained species it’s likely that the fetus passed through the birth canal much the way today’s gorilla fetus does: head down and body facing its mother’s abdomen from start to finish. There was one major difference, though. Because of the wider, oval-shaped inlet, the fetus would have had to turn its head to the side when it entered the birth canal—just as modern human fetuses do.
So, the first major change in human childbirth came about as a response to upright walking. As Lucy and her descendants mastered that task, they began to use their freed-up hands to make tools for cutting and scraping, and, eventually, weapons. Evolution soon favored those with the nimblest tool-making minds. Brains became bigger, and once again the female pelvis had to adapt.
Given the fact that the Australopithecus pelvis was still relatively roomy, it took thousands of generations before the fetal head got large enough to become an obstetrical problem. That crisis point was reached about 1.5 million years ago. As the fetal head enlarged, the maternal pelvis could grow only so wide in its attempt to accommodate; beyond a certain point, an awkward, wide-based gait would make it difficult for females to flee predators. Faced with a problem that could kill either or both of them and end the human race before it started, mother and fetus displayed that most human of traits: they compromised.
Here’s the problem in a nutshell: newborn babies, then and now, have heads that are just a bit too big to fit down the birth canal in the round fetal state. Take a look at a newborn’s head—his ears reach out nearly to his shoulders. If that head-to-shoulder ratio never changed, an average adult would have about a size 20 head, and there isn’t enough polyester in all of China to make a world full of baseball caps that big.
Getting that big fancy tool-maker’s noggin out of the womb with minimal damage to mother and fetus became one of the great engineering challenges of human evolution. It was more or less the same challenge faced by a man who gets carried away building a boat in his garage.
Imagine that the man starts out with a simple boat in mind, maybe a kayak or a canoe, something he can paddle around the park lagoon on a Sunday morning. As the project unfolds, though, his imagination catches fire. Why just a simple little tub, he thinks? Why not a sailboat, or a ketch, or a schooner? So he adds bulwarks and gunwales and a crow’s nest. Soon he’s upgraded his little canoe to an oceangoing yacht capable of winning the America’s Cup.
One problem, though. His boat is now way too big to fit out the garage door. The man is left with two options: make the boat smaller, or the opening bigger. In the end he does a little of both—he lowers the crow’s nest and widens the doorway—and one morning, to much fanfare, the SS Show Off squeezes ever so carefully out the door and into the big lagoon of life.
That, minus the crow’s nest, is the story of the coevolution of the human head and the female pelvis.