“This smart and fun read is full of ‘who knew?’ moments that show in fascinating detail how birth has affected our culture in so many ways—even explaining the origins of gossip. Mothers, non-mothers and those who don’t want to think about all the messy details of childbirth will find this a gripping read.” —Kate Zernike, The New York Times

“Well-written and will be an important eye-opener to many.” —Publisher’s Weekly

“A clever, almost irreverent look at an enduring everyday miracle.” —Entertainment Weekly

“Tina Cassidy’s Birth: The Surprising History of How We Are Born is a fascinating ride through centuries of childbirth practices—from the days when midwives reigned to the dawn of male doctors, from the modern natural-birth movement to the astronomical increase in C-sections—and all the bizarre gadgets and lore in between. Cassidy’s spirited writing makes this historical account read like a compelling novel.” —Melissa Chianta, Mothering

“A startling journalistic take on birth practices over the centuries. . . . Fascinating.” —FitPregnancy

“As Tina Cassidy describes it in Birth—and she is persuasive—our choices about where, how, and even when to give birth are guided, if not limited, by a culture that shapes us much more than we realize. . . .[Birth] has real value for women who want to understand why the reality of giving birth didn’t match their careful plans and expectations.” —Alexandra Bowie, The New York Sun

“A rich cultural history of the subject.” —The Philadelphia Inquirer

“Replete with interesting facts about the physiology, politics and pieties of birth across the ages.” —Daily Press

“This history of childbirth is both a literary and a medical history achievement and belongs in any library strong in either medicine or feminist perspectives. An outstanding survey, this moves beyond the usual medical focus into the lives and experiences of woman giving birth.” —The Midwest Book Review

“The history of birth, as Cassidy deftly tells it, might well be summed up as What No One Ever Expected When They’re Expecting: Crank-and-pulley birthing systems and fish-bladder vacuum extractors. Man-midwives in drag and obstetricians trained on ‘mock mothers.’ With wit and aplomb, Cassidy covers the ongoing march of birthing fads, from the surreal horrors of the Twilight Sleep to Lamaze, doulas, and the current craze for elective C-sections.” —Mary Roach, author of Stiff: The Curious Lives of Human Cadavers and Spook: Science Tackles the Afterlife

“After all my training and years of practice, it’s easy to lose the historical perspective on childbirth, especially in a field that is constantly pushing new technological boundaries. It’s a joy to read and recommend a book that looks at where we’ve come from to show us how we might move ahead.” —Shari Brasner, MD, OB/GYN, Attending Physician at Mt. Sinai Hospital, New York, author of Advice from A Pregnant Obstetrician

“It’s as true of feminism as anything else that if we don’t know our history we’re condemned to repeat it. A liberating look at how assumptions have changed of what a good childbirth is supposed to be.” —Naomi Wolf, author of The Beauty Myth and Misconceptions

“It’s remarkable how little we know about the one piece of human history we all share: birth. Tina Cassidy has written a lively and informative journey through centuries of what women could really expect when they were expecting.” —Ellen Goodman, author of I Know Just What You Mean and Paper Trail

“Did they use forceps?” I asked.

“I think that they did, because of the condition that your head was in.”

“You don’t know if they used forceps?”

“I’d like to get those records,” she said, sounding sort of dreamy, her mind stuck in the labor room where she, too, delivered alone, no husband or family allowed.

“Scopolamine,” she said. “It makes you not remember what happened. I pretty much slept through it.”

When she was about to have my brother in 1976, my mother skeptically attended Lamaze classes, which then were in vogue. There she learned how to breathe—hee hee huhhhh—and her husband was prepped to witness the birth, a relatively new idea at the time. Though her “natural” delivery of me should have been proof that she could deliver this second child vaginally, her doctor gave her an X-ray to determine if her petite pelvis could allow for my brother to pass through. The doctor said her pelvic width was borderline and after just a couple of hours of normal labor, suggested a cesarean section. Unhappy with her first birth experience, she leaped at the opportunity. Spouses were almost never allowed in the operating room then. So my mother delivered alone. Again.

My youngest aunt had her first child in 1982, just as natural childbirth methods were peaking, a feminist backlash against the highly controlled births my mother and grandmother had gone through. Hers was the most unusual of all the Damaschi women’s labors to date, because her husband witnessed the whole event. But the birth of her second child, in a Catholic hospital in 1989, did not go as well as the first. Because of long-held religious beliefs that it is a woman’s station in life to suffer during labor—says so right there in the Bible—the facility did not allow for any pain relief. She was left alone in a room for hours, the baby facing backward in the birth canal, and she tore mightily at the end.

Despite all, I had high hopes for how the birth of my son, at a major hospital in the medical mecca of Boston, would unfold. I purposely chose a female obstetrician. Armed with a birth plan, the latest fad in obstetrical empowerment, I knew I would sail through labor wearing my favorite black spaghetti-strap nightgown—no johnnie for me! The lights would be dim, an epidural anesthetic juicing my spine only if absolutely necessary. I had written down my instructions for the nurses to read so that even if I was in too much pain to explain it to them myself, my plan would be clear.

An instructor at the hospital’s prenatal class told us that the episiotomy, a cut to make the opening of the birth canal wider, was no longer routinely performed by their obstetricians because they now knew that the incisions often caused more problems than they solved. The doctors also had abandoned stirrups because they had learned that having women lie flat with their legs in the air negates the powerful force of gravity for pushing out the baby. They said they didn’t routinely employ forceps anymore, which can injure the mother and child. And the doctors had stopped objecting to squatting, which opens the pelvis, an ancient practice that had been rediscovered after disappearing in the prudish Victorian era.

My husband and I felt blessed to have the latest thinking at our disposal. But after ten hours of labor and another four hours of pushing, the very busy obstetrician making rounds that night told us matter-of-factly that our son had not rotated all the way, and was stuck. I asked to have a midwife come and offer suggestions to move my labor along, but the harried staff said she was unavailable. I asked them to shut off the epidural (yes, I had succumbed the fifth time the nurse asked me if I wanted one), so that I could try other labor positions. They obliged but only, I think, because they were annoyed and knew the pain would be so severe I wouldn’t care what happened next. Indeed, that was true.

My son’s heart rate was fine, but things had dragged on too long, as far as the staff was concerned. The doctor insisted upon an emergency C-section—which was performed with the speed of a SWAT team—throughout which I vomited and shook violently, while my poor husband clung to my side of the operating curtain, careful not to glimpse my uterus, which rested outside my abdomen while the doctor stitched it. The next morning, my still-ashen spouse, grateful everyone was alive and the baby was perfect, cornered the doctor, wanting to know if the ordeal had really been necessary.

“What did they do in that situation before there were C-sections?” he wanted to know.

“The baby would have died in the birth canal,” the doctor said. “They would have had to wait for it to disintegrate, or they would try to get it out some other way, drilling a hole in the fetal head, emptying the contents and collapsing the skull, before it started to poison the mother.”

Well, then.

I caught this response as I shuffled out of the bathroom on my way back to bed. Too weak to react, I gingerly climbed beneath the blanket and filed a mental note to see if that was true. If I had lived five hundred years ago . . . I drifted into a fitful, clammy, bloated sleep, my body pumped even larger with fluids than it had been before the birth, while little George, softer and sweeter than heaven, lay wrapped up like a burrito in the crook of my arm, where I longed to keep him forever.

I was in a great deal of abdominal pain; it hurt more than I could endure to get in and out of bed. The doctor, following standard procedure, had cut through my taught belly skin, through a layer of fat, cauterizing along the way, until she reached the fascia, the glistening sheet, which looks like the filmy layer on a chicken breast, that undergirds the abdominal wall. She then nicked the fascia with the knife and extended the cut with scissors, pushing, not cutting, to tear the tissue like a sheet of wrapping paper. Once the fascia was peeled away, she pulled apart the muscles in the middle, poked a hole with her finger through a layer of tissue underneath, and stretched it hard. Using a clean knife, she cut ever so gently, and not too deep, into my uterus. She pulled apart the incision until it was big enough for the baby’s head and reached in elbow deep for the baby’s chin as an assistant pushed down hard from the top of the uterus. Someone, I’m not sure who, went between my legs and up inside my body to give him an extra boost before George popped out explosively, rather like a champagne cork.

I may have been in the hospital for the obligatory four long days, but there was no time to be a patient. I may have been a mom who was completely in love with my son, awed by him and stunned by how he came into the world, but I was also the primary food source for this amazing little organism, whose needs were constant and exhausting. I was discharged for home feeling utterly drained, my hormones roiling, my body viciously assaulted. All the while a nasty germ was breeding in the incision, forcing a trip back to the hospital, where an obstetrician prodded me with a Q-tip—incredibly, inside the wound—before sending me home in tears with an antibiotic prescription. Next came mastitis, a breast infection typical among novice nursing women.

So much for birth and nursing being “natural” processes. Surely, nature did not intend for any of this to be so difficult. If it did, how could the human race survive? Was I being a spoiled, wimpy modern woman? Was that why so many of my friends were having similar experiences? And if so, why were some women I know delighted by the whole affair, from first contraction to final push? Was my son too big? Was I too small? Were my boobs too sensitive? Should I not have succumbed to an epidural?

I’ve been a journalist for half of my life. I’ve covered Super Bowls and fashion shows, presidential campaigns and inaugurations, mob trials, bank failures, housing bubbles, kidnappings, and terrorism. I tried to make sense of all of those crazy stories by doing research and asking questions, whether it was pressing John McCain on his agenda while riding the Straight Talk Express or interviewing Tom Ford on a rose petal—strewn Milan runway. Through the frigid, blurry January, weeks after George was born, I found myself suddenly housebound with time to ruminate—though not with the time to cook or take a shower. Still, when George was peaceful, my mind returned to that nagging question: Why is birth such a crapshoot after all this time? I realized that I needed to use my professional skills to understand women’s bodies, the process of labor and birth, and the shockingly intense postpartum weeks. I needed to put into perspective my own experience. I needed to know what other women, in other cultures, in other times, had done.

When, finally, my infections had cleared and my scar had hardened into a thick red keloid, I embarked on a mission that became this book.

It began simply enough. Holding babe in arms, I awkwardly started to search the Internet. When I found little to satisfy my curiosity, I dragged myself to the library.

At first I was disappointed to discover that the most recent comprehensive world history of birth had been written more than fifty years ago. Even that, Eternal Eve, a British classic by Harvey Graham, was hard to find and badly outdated. There were a couple more recent books that focused specifically on American childbirth history, and I found plenty of anticesarean, pro-breast-feeding polemics, feminist and academic histories of midwives, and surveys of male-dominated obstetrics, but I knew these didn’t tell the whole story.

Indeed, much of what lined the shelves were how-to birth and breast-feeding guides, which were even more annoying now than they had been the first time I read them. There was no single source for the information I wanted, and clearly I was not the only one seeking it. The chatter on baby blogs was anxious. Women everywhere wanted answers to the same questions, from what other cultures use for pain relief, to why so many Dutch women give birth safely at home, to whether all women one day will have cesareans. Continuing my quest, I descended into vault like library basements, where the rare book departments and the microfilm rooms always seem to be located. It was in one of these windowless places that I found proof that my doctor wasn’t inventing that horrific tale of demise she told my husband: As early as the seventh century, desperate people were using hooks to perform craniotomies to extract a stuck child.

Suddenly even more motivated, I paged through the brittle parchment of sixteenth-century midwifery books, as well as vintage obstetric texts and hundreds of old periodicals. Eventually, I visited hospitals and birth centers; inspected antique obstetrical instruments in museums; attended a HypnoBirthing class; interviewed mothers, fathers, doctors, midwives, childbirth educators, hospital administrators, lawyers, academics, public health activists, and anthropologists. I spent days with nurses and anesthesiologists, witnessed single and multiple births, natural and cesarean. And sought out the latest trends. All to try to understand what is supposed to be a natural—perhaps the most natural—physiological process.

The more I learned, the more questions I had: How did midwives go from being burned as witches to vaunted by yuppies? Who let men in the room? Why would someone give birth in the ocean? What does the Titanic have to do with an ultrasound scan? Is there a link between Pitocin and autism? What did Queen Victoria have to do with epidurals? How is a woman’s pelvis undermined by eating Big Macs? Were cesarean sections really named after Julius Caesar? Could it possibly be true that even in early twentieth-century America, women delivering in hospitals were more likely to die there than if they had given birth at home? That poor women were used as obstetrical guinea pigs? That doctors use drugs to confine deliveries to banker’s hours? That some women have orgasms with vaginal births?

The answers—the surprising, frustrating, tantalizing answers—helped me realize that my childbearing experience, like my family’s chain of births, was merely a reflection of its time and place. My son’s birth may have been just as painful as the drawn out, agonizing vaginal birth that my mother had for me. But it was certainly different. (For starters, I was conscious and accompanied.)

And, of course, it could have been far, far worse. After all, my precious son is alive and well.

It is astonishing to me that we can touch the moon and predict the weather, map the human genetic code and clone animals, digitize a photograph and send it from Tokyo to Tehran with the touch of a button, but we can’t figure out how to give birth in a way that is—simultaneously—safe, minimally painful, joyful, and close to nature’s design.

As you will see, if history is our guide, we never will figure out the ultimate way to give birth. And we probably will never stop trying. For no matter that birth is the most natural of events, the arrival of a healthy baby is truly a miracle.

Evolution and the Female Body

I spotted Lucy, framed and hanging on the walls, in the bowels of the American Museum of Natural History. The three-million-year old fossilized australopithecine was a creature in mid-evolution between ape and Homo sapiens. She is one of the oldest human ancestors ever discovered.

Having just seen the expansive pelvises of knuckle-scraping apes and chimps in other displays in the museum, I was shocked to see Lucy’s pelvis, so tiny and elliptical from hip to hip that it could not have been easy for her to give birth, not even if the baby’s head was the size of a lemon. Staring at Lucy’s remains, I imagined the agony and ecstasy of birth since the beginning of time. And I thought about the connections between her bones and the advent of midwives, epidurals, surgical instruments, medical malpractice claims, a newborn with a cone head, and virtually every trendy technique that has come and gone throughout the centuries. It was clear that if we had ape-sized pelvises, we’d need no midwifery help, no sterilized stainless-steel paraphernalia, and no Demerol to give birth. But there would be other consequences.

Lucy, unearthed in Ethiopia in 1974, was related to those apes and chimps; she had long arms, short legs, and a face with apelike features. But she was clearly different in one respect. She walked upright. And there was her compact pelvis to prove it. As an evolutionary entry point, Lucy can help explain not just the physical aspects of human birth, which have become remarkably more difficult since we began walking upright and producing smarter offspring with the requisite larger crania, but also how primitive behaviors that may have existed in her era are still affecting labor and delivery today. Since Lucy’s lifetime, the female pelvis has remained narrow, so as to accommodate our walking upright, but it also has evolved in shape to accommodate the newborn head, which has grown in size over hundreds of thousands of years as the brain enlarged. Today, the upper opening of the pelvis is wide from side to side, as was Lucy’s; the lower pelvis, however, the baby’s exit, is widest from front to back. And therein lays the problem.

The obstetrical consequence of such a design is that human birth is, quite literally, a twisted process. In order to pass through the birth canal, the baby’s head—the largest part of its body—must rotate as it descends in a grinding pirouette. A baby monkey, on the other hand, does not need to turn: It emerges face up, having had plenty of room to simply drop down the chute.

The contrast between human births and those of four-legged mammals is stunning. Women have a much more difficult time than, say, polar bears, or the free-ranging howler monkey, which can deliver in about two minutes, as each has plenty of space in her birth canal. In fact, we are the only mammal species that needs assistance to give birth.

Although most animals seek solitude for birth, almost all women in labor ask for help or surround themselves with company. It’s as if somewhere, deep inside our brains, we cannot fathom how that baby’s big head can make a graceful exit. It’s a notion that causes fear, which triggers a cry for help in labor and delivery. According to American anthropologist Wenda Trevathan, such an impulse to call for aid could be an adaptive response to reduce mortality in a species more prone to obstetrical problems. This behavior probably developed around two million years ago, she says, along with the advent of consciousness. Once our brains were advanced enough to know that birth could be dangerous, the onset of labor made us scared. Fear often leads to the release of the hormone epinephrine, also known as adrenaline, which can stop contractions. To alleviate that fear—to keep labor progressing—women began asking for help from people they felt comfortable with: other women. Monkeys in labor often stop contracting when they know a human is watching them. Women aren’t necessarily different. After laboring at home for hours, many find their labor stalls when they arrive at the hospital, surrounded by the unfamiliar. The phenomenon is so common that doctors and nurses self-referentially call it “white-coat syndrome.” For women, being among strangers can retard labor.

Around the world, solitary human births are virtually unheard of. The exceptions are those peoples whose cultures support and value the concept. For example, women of the Igbo tribe of Nigeria may have a first birth supervised but a later one alone. Female members of the nomadic Pitjandjara tribe of Australia might deliver by themselves, behind the group, if there is no worry of trouble. So, too, do women of the !Kung San hunter-gatherers living in the Kalahari Desert in northeastern Namibia give birth on their own—for it is a sign of strength, esteemed in that culture. The story of a !Kung woman named Nisa is remarkable because it shows how even an uncomplicated birth among a people who enourage solitary delivery can be traumatic.

In the chilly depths of night, early in the twentieth century, Nisa gave birth to her first child in the bush without any help. When Nisa’s contractions had begun, she left her husband’s village, carrying only a blanket and an animal skin for warmth, walked a short distance, sat down on the sandy earth, and waited.

I leaned against the tree and began to feel the labor. The pains came over and over, again and again. It felt as though the baby was trying to jump right out. The pains stopped. I said, “Why doesn’t it hurry up and come out? Why doesn’t it come out so I can rest? What does it want inside me that it just stays in there? Won’t God help me to have it come out quickly?” As I said that, the baby started to be born. I thought, “I won’t cry out. I’ll just sit here. Look, it’s already being born and I’ll be fine.” But it really hurt! I cried out, but only to myself. I thought, “Oh, I almost cried out in my in-laws’ village.” Then I thought, “Has my child already been born?” Because I wasn’t really sure; I thought I might have only been sick. That’s why I hadn’t told anyone when I left the village. After she was born, I sat there; I didn’t know what to do. I had no sense. She lay there, moving her arms about, trying to suck on her fingers. . . . The cold started to grab me. I covered her with my duiker skin that had been covering my stomach and pulled the larger kaross over myself. Soon the afterbirth came out and I buried it.

Somewhat stunned, Nisa left the baby, still attached to the placenta by the umbilical cord, and ran back to the village. When her husband saw her bloody legs, he shouted for his grandmother to go and help cut the cord. The old woman promptly did just that.

According to Marjorie Shostak, a researcher to whom Nisa recounted her story, an uncomplicated delivery reflects a !Kung woman’s full acceptance of childbearing: “She sits quietly, she does not scream or cry out for help, and she stays in control throughout the labor. A difficult delivery, by contrast, is believed to be evidence of her ambivalence about the birth, and may even be seen as a rejection of the child.”

Thankfully, being alone during delivery is a rarity for most women today.

Our hormonal need to feel safe or have help during birth is not the only phenomenon that may be an adaptation from primitive times. Another amazing obstetrical fact is that most land mammals labor through the night. The squirrel monkey begins her labor between dusk and dawn. If delivery does not happen before morning, her contractions will stop and begin again after sunset. Natural selection might favor nighttime deliveries for some animals—like the squirrel monkey—that search for food during the day. A female who stops to give birth during such a busy time risks being left behind by her kin. Delivering at night also gives mother and offspring time to recover without the risk of being discovered by predators—or even those in their own social group who might want to inspect the new arrival. (The schedule is flipped for nocturnal animals: They tend to deliver during the day.)

Humans, as well, seem to prefer laboring through the night. But because delivery takes longer for people than for monkeys, women tend to give birth in the morning. Such a pattern may also reflect Lucy’s era, when it was advantageous to deliver with fellow tribe members around to provide assistance and protection. Those giving birth in the afternoon would likely have found themselves alone, as the others would have been looking for food. Also, laboring through the quiet of the night may keep the mother relaxed and therefore able to have faster, less complicated births.

But, as you might suspect, behavior that worked well on the savanna two million years ago may not be advantageous now. Most dilating women today arrive at the hospital during the late shift, when the staff is reduced and the least experienced doctors are working. More senior obstetricians have the privilege of working business hours, while exhausted residents, living on pizza and donuts and the occasional nap on a cot, attend to the overnight customers. Some women might be willing to forgive a resident who yawns through her contractions at 3:00 a.m. or rushes to the bed at the last second to catch the baby and cut the cord. However, the dearth of well-rested, experienced doctors working overnight, and the lack of hospital services that are available only during the day, can have devastating consequences.

Babies born late at night have as much as a 16 percent greater chance of dying than babies born between 7:00 a.m. and 7:00 p.m., a 2005 study found. This spike in overnight infant deaths may be attributed to the quality and number of doctors and nurses during those dark hours.

There are other ways that life in the developed world hasn’t mixed well with the ancient biological process of birth. Take, for example, modern eating habits. Easy access to food is yielding bigger babies that, no matter how hard they try, simply cannot fit through the standard-issue pelvis. This imbalance is called cephalopelvic disproportion, or CPD in E.R. language, and is an increasingly common reason for cesarean sections.

Dietary changes affected obstetrics hundreds of years ago, as well, during the period of rapid industrialization and urbanization, which severed populations from fresh milk, green vegetables, and sunlight. Calcium and vitamin D deficiencies led to a bone disease called rickets, which deformed women’s already tight pelvises, resulting in countless deaths for mother and baby. The disease was so pervasive that much of the early research and practice for cesareans involved pregnant women with rickets.

Thinking about all this, I peeled away from the display case of Lucy’s bones. The sights and sounds of humanity shuffling across the museum floor suddenly reentered my consciousness. I turned and happily saw the throng of well-fed women inching strollers through the café line. Obviously, children—and their mothers—were today regularly surviving birth. How? These women were all taller than Lucy, who stood less than four feet high; their pelvises certainly were somewhat larger. But their babies’ heads are more than twice the size of what they would have been in Lucy’s time. Proportionately, we still seemed to be losing the battle with evolution.

Back at home, I phoned Owen Lovejoy, professor of biological anthropology at Kent State University in Ohio and of human anatomy at Northeastern Ohio Universities College of Medicine. Lovejoy often can be found brushing through the dirt at fossil excavation sites around the globe, or sitting on the witness stand in high-profile homicide cases.

“Lucy’s pelvis was so small!” I said.

Lovejoy laughed and explained that women today are indeed better off than Lucy was, in purely obstetrical terms, but perhaps not by much.

“Because we have her pelvis, we know something about pelvic evolution among humans,” Lovejoy explained. “Lucy’s pelvis is beautifully adapted to upright walking, but it’s poorly adapted to giving birth to a large-brained fetus. And so between Lucy as a starting point and modern humans, we changed the pelvis—not for bipedality but to get that huge cantaloupe through,” he explained.

No wonder birth doesn’t always go smoothly. The physical frame leaves little room for error. Lovejoy explained that the birth canal became larger, but, more important, it also became different in shape, with the exit now widest between the pubic bone and the tail bone. As a result, the big head is able to descend through a pelvis fine-tuned for walking, though not easily. Assuming the baby is not breech—being born feet or buttocks first—its head must enter the pelvis facing up toward the pubic bone, with the widest part of its head—ear to ear—lining up with the widest part of the pelvis—hip to hip. But, as mentioned, that has to change quickly. The baby must begin to turn sideways, as much as forty-five to ninety degrees, in order to align itself with the widest pelvic outlet, its head emerging face down, rather than face up. In most cases, babies can navigate the space unaided. But not always. Sometimes the space is just too small and the head is too big, so the aforementioned cephalopelvic disproportion becomes a factor.

Birthing babies with large crania would not be an issue if humans had pelvises like chimpanzees, our closest genetic relatives. But if we had pelvises like chimps, we would also walk like chimps, rocking from side to side as if wearing snow shoes. The stance would be an uncomfortably wide, inefficient, and exhausting means of getting around.

Although women’s pelvises are universally narrow compared with those of other primates, they vary enough in shape that there are four categorizations for them. If she is lucky, a woman has a “gynecoid” pelvis, the most common and successful shape for birth because it is the most spacious and round. The other shapes—android, resembling a funnel or a narrow heart similar to a male’s pelvis; anthropoid, a thin oval; and platypelloid, with a mildly deformed kidney-shaped brim—can also accommodate a baby, but only if they are simpatico with the child’s size.

Brand-new babies may appear tiny, especially in those first days, when their fingernails are perfect little specks and their knees are as sweet and wrinkled as shriveled figs. But it doesn’t matter if they’re five pounds or eight: Human newborns—and their heads—are proportionately much larger than what other mammals deliver. Female gorillas produce offspring that average only about 2 percent of their mother’s weight, compared with 6 percent for humans. Polar bears, who weigh more than five hundred pounds, give birth to cubs with heads smaller than those of human newborns.

Still, anyone who has ever pushed for hours on end only to have the experience culminate in a grapefruit-sized head tearing her flesh might be surprised to learn that while human babies’ crania are huge by comparison with those of other animals, their brains aren’t as large as they should be.

Lucy’s offspring would have needed a tiny head to pass through her small frame. By the later part of the Stone Age, a couple of hundred thousand years ago, the Cro-Magnons appeared in what is now Europe. Their crania—and those of their offspring—had expanded to accommodate all that newfound intellect used to invent religion and draw deer on cave walls using berry juice.

“Brains appear to have gotten bigger progressively throughout the last two million years,” said Lovejoy. “But we did hit a wall. The wall we hit was we just couldn’t make the pelvis any bigger, so what we had to do is start giving birth to a more altricial infant.”

Altricial means that the baby is essentially born helpless. Throughout early human history, brain development made fetal head size grow, but only to the point that it still had a chance to fit through the pelvis. The sorry truth is that babies’ crania are actually so small as to be underdeveloped for our species, much more underdeveloped than those of other newborn primates. Human babies compensate by quadrupling brain size after birth. In contrast, most other primate offspring emerge with pretty well-developed brains, having only to double the cranium after birth.

Because human infants are born with their neural networks incomplete, leaving them writhing, helpless squawkers who need constant care during the first year of life, the baby’s first three months outside the womb are a period of rapid growth, what many scientists refer to as a fourth trimester of development. Other scientists look at infant growth as a two-stage gestation: thirty-eight weeks in utero, followed by thirty-eight weeks outside. Most infants begin to crawl at around nine months of age—the end of the theoretical second stage of gestation—a marker that brings their brains closer to the development level of a deer’s when it is born. A deer can run shortly after birth. A baby ape can cling to its mother moments after coming out. But if a human was born with a cranium large enough to make it as developed as the brand-new deer or ape, its head would be too large to fit through the birth canal. For a human baby to emerge as developed as a newborn elephant— which has a 630-day gestation—the child would need to be born with a cranium the size of a one-year-old’s, a physical impossibility. Instead, the baby comes out as immature as an infant opossum or kangaroo, which remain protected by a mother’s pouch for a long while after birth. It’s no wonder tiny babies are cranky. They’re really not ready to live outside the womb.

Intelligence and upright walking, the two things that have made human beings so special among mammals, are features that are in direct competition when it comes to survival of the species. Head size may want to expand as we have better nutrition and more doctoral candidates, but nature must keep it in check with pelvis dimensions so we can continue walking on two legs.

“The result of these conflicting requirements,” Trevathan writes, “is a species with obstetrical problems and mortality related to birth that is rare among undomesticated animal species.”

If we had just one more inch of pelvic width, there might be no need for cesareans, forceps, vacuums, extraction hooks, and episiotomies. And birthing a baby might not hurt as much. Instead, women and their birth attendants roll the dice virtually every time to see if the parts will align. That leads to a sensible question. Why not eliminate the guessing before labor begins? Can’t doctors measure the mother’s pelvis and the fetal head well before contractions start or even after they begin? Can’t they deduce whether a vaginal delivery will be possible?

Taking Measurements

Scientific attempts to evaluate the width of the birth canal date back to the period of rapid industrialization and urbanization, which severed populations from fresh milk, green vegetables and sunlight. Calcium and vitamin D deficiencies could lead to the bone softening disease called rickets. At the height of the Industrial Revolution, as much as 60 percent of children living in cold-climate urban areas in Europe and North America had developed the disease, leaving many of them with bowed legs, crooked backs, or warped pelvises, which proved especially dangerous for girls if they ever became pregnant. Two hundred years would pass before researchers determined, in the 1920s, that exposure to sunlight and fortifying the public milk supply with vitamin D, helped reduce the incidence of the disease. Rickets is still a problem in less developed countries, especially among darker-skinned peoples and even Muslims, who go about heavily robed. And the problem recently reemerged in the United States, where doctors saw a cluster of rachitic children living in an underprivileged New York neighborhood where they rarely ventured outside out of fear of random violence. Dark-skinned children, in particular, need extra sunlight to help their bodies absorb essential nutrients.

In the eighteenth and nineteenth centuries, doctors used a pelvimeter, an instrument that looked like a giant pair of tweezers with the ends of the pincers curved inward, to determine the size of the birth canal. At the hand-held base of the instrument was a measuring device for reading how far the pincers spread out inside the woman. In some of the worst cases, the pelvic opening was as small as a quarter.

By the early years of the twentieth century, following German physicist Wilhelm Röntgen’s discovery of the X-ray, science had moved on. Doctors soon were using the X-ray not only to measure the fetal and maternal pelvis, but to look for abnormal fetuses, twins, and placenta problems. Röntgen’s technique required the mother to lie on a table while the radiation was zapped in the general direction of the unborn. Though Röntgen won the Nobel Prize in 1901 for his discovery, the medical application was not perfect. The pregnant belly, padded with fat, placenta, and amniotic fluid, put quite a bit of distance between the camera and its subject. The greater that width, the more distorted the X-ray. Doctors tried to compensate for this by applying an algebraic formula on a simple slide rule. Although X-rays could diagnose extreme situations—twisted pelvises, fetuses with water on the brain—the pictures were not as useful for determining whether an average baby would fit through an average pelvis.

An additional unnerving aspect of this use of X-rays is that doctors were not initially aware that exposure could be harmful to the mother and fetus. When Herman J. Muller first reported in Scientific Monthly in 1928 that he was able to mutate fruit flies with x-radiation, doctors began to suspect that the technology could be damaging, especially to developing organisms. By 1942, however, with the advent of new developer processes that required less radiation, X-rays again were proclaimed to be safe. But in 1960, a standard textbook, Antenatal and Postnatal Care, sounded the alarm again, saying, “It is now known that the unrestricted use of X-rays may be harmful to mother and child.” Two years later, an article in the Journal of the National Cancer Institute linked obstetric X-rays to leukemia.

Despite these warnings, X-rays were a tool doctors had come to rely on. And they had nothing with which to replace it—until the now ubiquitous ultrasound came along in the late 1960s. Pregnant women today don’t fear that their ultrasounds will cause any harm. Instead, they look forward to the scan with anticipation, learning whether the fetus should be named Louis or Lilah—sometimes there is a Louis and a Lilah—and whether there are any abnormalities. The ultrasound can also help narrow a due date and determine whether the late-term fetus is in an awkward position for birth.

As useful as ultrasounds are, they can’t predict with a normal pregnancy whether the baby will fit through the exit. For one thing, pregnancy hormones can change the size of the birth canal by loosening ligaments that bind the bones. In rare cases, everything can get so loose down there that the cartilage attaching the two halves of the pelvis at the pubic bone becomes unhinged. Because of these hormones and individuals’ differing abilities to stretch, doctors can’t predict how much the pelvis will open during labor.

Another unknown is the malleability of the baby’s head. The fetal skull has six fontanels, which are soft, membranous areas between the unjoined sections of bony plates. At term, the plates are thin and pliable and often overlap as the head is compressed during the journey through the birth canal. It’s impossible to know how much the head will mold—every baby is different.

Yet despite these uncertainties, modern technology has eased childbirth for millions of women. If only our modern diets could be said to be doing the same.

The Fast-Food Phenomenon

Whereas Lucy had a diet of nuts, berries, and the occasional piece of meat, her modern descendants are gorging on cheeseburgers, onion rings, ice cream, chips, and whipped cream—topped mocha lattes. There’s a fatty, salty, fried, or frozen vice for every maternal desire. And moms aren’t the only ones gaining excessive weight during pregnancy. Babies are getting bigger, much bigger, in countries where food and good pregnancy care are plentiful.

According to Guinness World Records, Carmelina Fedele of Italy gave birth to the heaviest baby on record. Her toddler-sized infant, born presumably by cesarean in Aversa in 1955, weighed in at 22 pounds, 8 ounces. Of course, the baby was an anomaly, most likely the result of runaway gestational diabetes. But babies in developed countries are indeed being born heavier. Even a cursory check of English-language newspaper stories from 2005 shows how increasingly common jumbo newborns have become, from a Texan named Angel Gabriel (13 pounds, 9 ounces, by cesarean) to English baby Charlie Stokes (15 pounds, 2 ounces, via a “horrific” vaginal birth, according to his mum).

In Australia, a 2002 report found that there had been a 12 percent increase since 1993 in the proportion of babies weighing more than 9.9 pounds at birth. In Ireland, researchers at Dublin’s famous Rotunda maternity hospital looked at birth weights for first time mothers and found that between 1950 and 2000, millennium newborns weighed an average of 7 pounds, 10 ounces, about a pound more than they did a half century earlier. The news is the same across the United Kingdom. A headline in the Sunday Times (London) in 2003 screamed, “Better British diet gives birth to mega baby.” The story said the proportion of babies weighing 9 pounds, 15 ounces, or more, a classification benchmark for large children at birth, rose 20 percent in ten years. A doctor quoted in the piece blamed the drive-through menu, in part, for many of the larger babies.

“Mums with a diabetic tendency and obese mums tend to be more likely to have bigger babies because there is more fat laid down and more sugar present,” said Dr. Alan Cameron, a consultant obstetrician at the Queen Mother’s hospital in Glasgow. “The fast-food diet also predisposes to increased gestational diabetes, which develops in pregnancy.”

In Britain and America, a typical newborn weighs in at about 7 pounds, 8 ounces. Swiss newborns weigh an average of about 8 pounds, with mothers there producing more and more 13 pounders. These are robust infants, especially compared with those in less developed countries across Asia and Africa. Indian babies, for example, average about 6 pounds.

Why such a boost in birth weight in so short a time? These large babies are not the result of evolutionary changes, which could take thousands of generations to permanently alter human physiology; rather, they are by-products of the rapidly shifting environmental and cultural landscape. Between 1920 and 1975 three generations of women dieted throughout their pregnancies to make sure they did not gain more than the 15 to 20 pounds their obstetricians advised, knowing larger babies came with a big price. It wasn’t until the late 1970s that doctors relaxed weight gain limits, acknowledging that if a pregnant woman was hungry, her fetus probably needed her to eat. Since then, expectant mothers have been more happily eating for two within the recommended range of 25 to 35 pounds. Few doctors bat an eye if a woman gains more than 40 pounds. Most doctors now say that the amount women should gain depends on her pre-pregnancy body mass index, with thin women needing to gain more than heavy ones.

In addition to consuming more calories, pregnant women are also generally healthier than they used to be. They pop vitamins and folic acid, and they are avoiding alcohol, tobacco, and even caffeine. To glean how much of a shift in behavior this all is, crack the spine of a dusty guidebook for pregnancy called Safe Convoy, published in 1944. The book says there is no scientific reason for a moderate smoker to stop when she is expecting, because to quit “at that time may do more harm than good by upsetting the nerves. A good rule for smokers is ‘less than a pack a day.’” In an equally startling interview on Face the Nation in 1971, the chairman of the board of Philip Morris, confronted with evidence that smoking in pregnancy leads to low birth weight, famously said: “Some women would prefer having smaller babies.”

While the good news is that the weight increase is likely because women are healthier during pregnancy—excluding diabetes from the discussion—the bad news is that the birth canal is not getting larger, because there is not enough genetic variation in the mating pool for that to happen. And so the sudden increase in larger babies has contributed to the tripling of cesareans during the same time period.

If doctors could accurately predict cephalopelvic disproportion (CPD), many long and painful labors might be avoided. Obstetricians once considered large parental shoe size to be the best indicator for CPD. Now they say that if both parents have large heads in relation to their height, chances are good the baby’s head will be larger than its mother’s pelvis will allow. Armed with that information, an obstetrician might just recommend surgically removing the baby.

Continuing on this trajectory of producing larger and larger babies may eventually have other evolutionary consequences, in which twins and premature births are actually advantageous. Think about this: With twins, while the total weight of the fetuses may be greater than a single baby, they generally are each smaller than one child in utero might be, allowing the mother to birth each of these smaller babies more easily than one large one. A single large fetus might run out of room in the womb before it reaches full development. A premature birth, in that situation, may well be an adaptation to a problem.

More research on that interesting possibility isn’t really feasible, however, because modern medicine so quickly turns to the knife. Doctors are easily bypassing the possibility of CPD by performing cesareans. In early 2005, another English woman, a hotel chef married to a fishmonger, gave birth two weeks early to a boy nicknamed Mighty Joe. He weighed 13 pounds, 13 ounces. Mother Sara Griffin, whose diet consisted not of Big Macs but of mussels, cockles, and all sorts of seafood during the pregnancy, had an emergency cesarean after an exhausting seventeen-hour labor. “As soon as I came round from the anesthetic, one of the nurses told me he was the biggest baby that had ever been born there,” said Griffin, who is 5 feet, 8 inches. “I was gobsmacked. Thank God for anesthetics.”

Is Sara Griffin’s story a harbinger of where birth is headed? For an answer, I turned to Professor Lovejoy again, hoping he could explain if there’s a way to exit this loop of having large babies and needing cesareans.

“How will this story end?” I asked him.

“Given the rate of technology, one hundred years from now no one will be giving birth. We’ll make children up from artificially conceived fetuses, all done technologically,” he said mischievously. “What people don’t realize today is the explosive advancement of technology that can override evolution. We override evolution to make better tomatoes. There’s no reason we can’t override evolution to make better humans.”

And so the pelvis, obstetrically speaking, could be made obsolete.

It’s clear that survival of mother and child depends on many things, from pelvis shape and head size to the position of the baby and physical abnormalities. And it seems evident that evolution’s legacy and modern life seem to be increasingly at odds. But the situation is far from hopeless. In fact, while a woman’s labor may take longer than a monkey’s or hurt more than a polar bear’s, human birth does succeed in the vast majority of cases. There are 6.5 billion people on this planet to prove the point.

The missing link in all this modern-day success may be the midwife. Although Lucy’s own brain might not have been developed enough to make her fear birth and seek help—we just don’t know—eventually women came to rely on having companionship to guide them through it. These helpers became the human solution for overriding nature’s glitches.