The Obstetrics Dilemma and the Design of the Human Birthing Process
The birth of a child is a marvel to behold. In fact, you might even call it a miracle.
Ironically, many skeptics would point to the human birthing process as an example of a flawed and imperfect biological system. It’s anything but a marvel, they say. Anything but a miracle.
Difficulties of the Human Birthing Process
In some respects, I understand why they would take this position. The human birthing process is difficult. It’s painful and dangerous for both the mother and child. Often the birthing process is complicated by an obstructed delivery. By comparison, for nonhuman primates the process of giving birth is relatively easy and free of the complications characteristic of human births.
An Evolutionary Origin of the Human Birthing Process?
In light of theses difficulties and dangers, skeptics maintain that the human birthing process is best explained as the product of our evolutionary history. Why would a Creator make human beings—the crown of creation—suffer through a poorly designed birthing process?
Many evolutionary biologists think the difficulties associated with giving birth arise from what’s called the “obstetrics dilemma.” In fact, recent work by a team of anthropologists from Europe seems to uphold this perspective.1
The obstetrics dilemma posits that the origin of the human birthing process represents a compromise between two evolutionary pressures. The first arose from the shift of our knuckle-walking ape-like ancestor to a bipedal hominin. The second arose from the increased size of the human head. These two factors restricted the size of the human birth canal and made the passage of a large-headed infant through the birth canal difficult.
Many biologists see the obstetrics dilemma as precisely the type of biological system that evolutionary processes produce. According to many evolutionary biologists, evolutionary processes don’t produce well-designed, optimal systems. Instead, the unguided, undirected processes of evolution yield flawed, poorly designed systems. These systems emerge through a process constrained by evolutionary history in which new systems are cobbled together by co-opting and modifying preexisting systems.
For evolutionary biologists, the human pelvis evolved from the pelvis of a knuckle-walking ape-like creature—a pelvis best suited for creatures walking on all fours, not a creature that stands erect and moves around on two feet. Presumably, evolutionary forces narrowed the pelvis as hominin bipedalism emerged. Consequently, the opening of the birth canal became smaller in humans, making it more difficult for the baby’s head to pass through the birth canal. As hominins evolved toward modern humans, fetal head size increased, further compounding this restriction. This increase made a child’s passage through the birth canal even more challenging.
Presumably, the obstetrics dilemma forced a comparative shortening of gestation in humans. This shorter pregnancy ensures that the growth of the fetus’s head doesn’t progress beyond the point that he or she can’t enter and pass through the birth canal.
Due to shorter pregnancies, the development of the human brain must continue outside the womb, a process called secondary altriciality. At the time of birth, the head size of the human neonate (newborn) is about 28% the size of an adult’s. By comparison, the head size of a chimpanzee neonate is about 50% the size of an adult’s. Despite this difference, the neonate head size of chimpanzees is still smaller than that of humans, so the birthing process for chimpanzees (and other great apes) is largely free of complications.
Another consequence of the obstetrics dilemma is that humans require assistance during the birthing process. Evolutionary biologists refer to this requirement as cooperative breeding.
New Insights into the Origin of the Obstetrics Dilemma
Recently, a team of researchers from Europe sought to understand the evolutionary origin of the human birthing process and establish support for the obstetrics dilemma. The anthropologists chose to study the birthing process for the australopithecines because these creatures are viewed as transitional forms leading to the evolutionary emergence of modern humans. Australopithecines had the capacity to walk upright, yet they had a relatively small brain size. (For reference: the average brain size of chimpanzees is around 400 cc [cubic centimeters]; the average brain size of Australopithecines was about 450 cc.; and the average brain size of modern humans is about 1200 cc.)
By studying the birthing process of the australopithecines, the researchers could tease out the relative contributions that the narrow pelvis and large head size make to the obstetrics dilemma. The team accessed australopithecine pelvises from the fossil record. The fossils allowed the team to reliably estimate the size and geometry of the australopithecine birth canal. To date, no australopithecine neonate remains have been recovered. To determine fetal brain size, the research team turned to estimates previously published in the scientific literature. These estimates ranged from 110 g to 180 g. For their study, the team used three head sizes: 110 g, 145 g, and 180 g.
They then modeled the birthing process using 3-D computer simulations and learned that only fetuses with a head size of 110 g would pass through the narrow australopithecine birth canal. The head size estimate of 110 g assumed that the head size of the australopithecine fetus was 28% that of the adult’s, just like it is for modern humans.
The results of this study are based on computer modeling. As such, caution is in order interpreting their results. Given that caveat, I will take their results at face value. The researchers concluded that the primary contributor to the obstetrics dilemma is the narrowing of the human pelvis due to the evolutionary shift to bipedalism. Even with a relatively small head size, the australopithecine fetus would have had difficulty making its way through the birth canal because of the narrowed pelvis. The team also speculated that because the fetus’s head size would be 28% as large as an adult’s, the australopithecines practiced cooperative breeding and experienced secondary altriciality (head growth after birth)—just like modern humans.
The researchers conclude that their results provide added support for the obstetrics dilemma. This conclusion is significant for evolutionary biologists because some anthropologists question the obstetrics dilemma. Those who question the model argue that the shortened gestation and secondary altriciality in modern humans is driven by metabolic considerations, not concerns about obstructed deliveries.
According to this alternate model, the human fetus’s disproportionately large brain requires a relatively high level of calories and nutrients. As the pregnancy progresses, the mother can no longer supply the nutrition needed for the fetus’s brain to grow and develop in the womb. Therefore, the gestational period becomes shortened and secondary altriciality results.
The work by the European scientific team doesn’t invalidate the metabolic demand model, but it does lend direct support for the obstetrics dilemma. And, from a big picture standpoint, studies like this one seemingly evince an evolutionary origin for humanity.
A Creation Model Perspective on the Obstetrics Dilemma
Is the evolutionary paradigm the only way to interpret the obstetrics dilemma? Is it possible to view the obstetrics dilemma from a creation model or a design perspective?
I think so. Instead of viewing the human birthing process as a flawed design that reflects the constraints of a historically contingent evolutionary process, I see it as an optimally designed process that meticulously balances several trade-offs—just the type of system that would be designed by a Creator.
Trade-offs are an inevitability in engineering. Systems intended to accomplish multiple objectives—some of which conflict—inevitably face trade-offs. In these cases, each facet of the system can’t be optimized. Instead, the system’s components must be intentionally made suboptimal, carefully balancing the competing objectives of the system to achieve overall optimal performance.
The human birthing process exemplifies this engineering concept. It reflects the perfect compromise that allows for fetuses with large heads (and brains) to be birthed by a creature who stands and walks upright. Other features of the birthing process and human growth and development can be viewed as compensatory designs that help to mitigate the difficulties of the birthing process caused by the baby’s large head and the narrowing of the mother’s birth canal. These compensating designs include secondary altriciality, cooperative breeding, the twisted birth canal, and the newborn’s malleable head.
In short, when the basic constraints of engineering are considered, it becomes evident that the human birthing process has been designed to expertly manage competing and conflicting objectives. This type of system isn’t necessarily expected from an evolutionary standpoint. But it is the type of design expected to come from a master engineer. In other words, it is rational to think that the human birthing process is, indeed, the handiwork of a Creator.
But what about the anatomical and physiological features shared by humans and other primates?
From a creation model / design framework, shared features among the birthing processes of humans and other mammals—including nonhuman primates and the hominins—reflect common design, not common descent.
Evolutionary Constraints or Constraints of the Archetype?
Yet, based on my experience, sophisticated skeptics will insist that even though the design of the human birthing process may well be optimal, it is still more reasonable to view it as a product of evolutionary history. They ask, Why wouldn’t a Creator with infinite power and infinite resources design humans in such a way as to avoid trade-offs such as those connected to the obstetrics dilemma?
It’s a fair question.
In effect, skeptics argue that God should have created human beings with a unique anatomy and physiology to specifically accommodate our bipedalism and large head size. What if he had?
It would solve the problem of trade-offs in one respect, but that doesn’t mean the design of the human body would be free of trade-offs entirely. They are inevitable for complex systems. Any design used to construct the human body would face trade-offs. It’s just that the trade-offs would appear somewhere else.
From a creation model perspective, trade-offs in biological systems arise, in part, from the constraints of the archetypical designs shared by organisms that naturally group together. Prior to the publication of Charles Darwin’s On the Origin of Species, biologists such as the eminent Sir Richard Owen interpreted shared biological features as arising from archetypical designs that existed in the Mind of the First Cause. These designs manifested in biological systems as homologous structures. Owen marveled that the archetypical designs that define the anatomy of organisms that naturally grouped together were so robust that they could be varied to produce biological systems that perform a wide range of functions.
In this vein, it’s remarkable that the design of the mammalian pelvis and gestation is so robust that it can be varied to accommodate two distinct modes of locomotion: knuckle-walking quadrupedalism and upright bipedalism, along with the large human head and brain.
Designed for Discovery
The use of archetypical designs has another important consequence. Shared biological features allow life scientists to generalize what they learn when they study one organism to the entirety of the biological realm. Shared designs make it possible for biologists to use model organisms. For example, by studying the comparative anatomy and physiology of the birthing process in humans and nonhuman primates, the European scientists developed insight into the birthing process of the australopithecines.
Conversely, if the Creator used a near-infinite array of biological designs, it would be challenging to study the living realm. The process of discovery in biology would be cumbersome and laborious.
In short, shared biological designs make nature intelligible. And that’s a marvel—even a miracle.
The Elegant Design of Human Reproduction
“The Remarkable Scientific Accuracy of Psalm 139” by Fazale Rana (blog)
“Placenta Optimization Shows Creator’s Handiwork” by Fazale Rana (blog)
“Recent Insights into Morning Sickness Bring Up New Evidence for Design” by Fazale Rana (blog)
“If God Hates Abortion Why Do So Many Occur Spontaneously in Humans?” by Fazale Rana (blog)
“The Female Brain: Pregnant with Design” by Fazale Rana (blog)
“Curvaceous Anatomy of the Female Spine Reveals Ingenious Obstetric Design” by Virgil Robertson (article)
“Life’s Twists and Turns Are Designed to Start in the Birth Canal,” by Fazale Rana (blog)
Design Constraints of the Archetype
“Archetype or Ancestor? Sir Richard Owen and the Case for Design” by Fazale Rana (article)
“Q&A: Why Would a Limitless Creator Face Trade-Offs in Biochemical Designs?” by Fazale Rana (blog)
“Q&A: Why Would an Infinite Creator Employ the Same Designs?” by Fazale Rana (blog)
“Duck-Billed Platypus Venom: Designed for Discovery” by Fazale Rana (blog)
1. Pierre Frémondière et al., “Dynamic Finite-Element Simulations Reveal Early Origin of Complex Human Birth Pattern,” Communications Biology 5 (April 19, 2022): 377, doi:10.1038/s42003-022-03321-z.