ArticleProceedings of the National Academy of Sciences of the United States of America2016
Cliff-edge model of obstetric selection in humans.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 43 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
43 citing papers in PubMed, 94 citations in OpenAlex.
- Humans are not unique: difficult birth is common in placental mammals.Biological reviews of the Cambridge Philosophical Society · 2026Review
- Insights into Neanderthal development, childbirth, and locomotion from the Palomas and Dederiyeh pelves.Proceedings of the National Academy of Sciences of the United States of America · 2026Article
- Organ Size and Metabolic Rate Co-Vary with Dimensions of the Obstetric Pelvis: The Metabolic Coordination of Childbirth Hypothesis.American journal of biological anthropology · 2026Article
- Conflict, Constraint, Cooperation, and Allocation: A Plural Evolutionary Architecture for Human Reproductive Paradoxes.American journal of biological anthropology · 2026Article
- Falling fertility on the left as key driver of US birth decline.Scientific reports · 2026Article
- Disclosure and consent: ensuring the ethical provision of information regarding childbirth.Journal of medical ethics · 2025Article
- Proximate and ultimate causes of pregnancy sickness.Evolution, medicine, and public health · 2025Review
- Maternal-fetal conflict and the timing of birth.Evolution, medicine, and public health · 2025Review
- 'Everyone in my family has C-sections': increased likelihood of caesarean birth in family lineages in the United States.Evolution, medicine, and public health · 2025Article
- Gradual exacerbation of obstetric constraints during hominoid evolution implied by re-evaluation of cephalopelvic fit in chimpanzees.Nature ecology & evolution · 2024Article
- Obstructed Labor, Evolution, and Health Disparities.Biology · 2024Review
- Review
- Reconsidering the developmental origins of adult disease paradigm: The 'metabolic coordination of childbirth' hypothesis.Evolution, medicine, and public health · 2024Review
- Social-ecological niche construction for sustainability: understanding destructive processes and exploring regenerative potentials.Philosophical transactions of the Royal Society of London. Series B, Biological sciences · 2024Article
- Magnetic resonance imaging pelvimetric measurements as predictors for emergent cesarean delivery in obstructed labor.European journal of obstetrics & gynecology and reproductive biology: X · 2023Article
- There is an obstetrical dilemma: Misconceptions about the evolution of human childbirth and pelvic form.American journal of biological anthropology · 2023Review
- Evaluation of dual-energy X-ray absorptiometry compared to magnetic resonance imaging for collecting measurements of the human bony pelvis.American journal of human biology : the official journal of the Human Biology Council · 2022Article
- Dynamic finite-element simulations reveal early origin of complex human birth pattern.Communications biology · 2022Article
- Human shoulder development is adapted to obstetrical constraints.Proceedings of the National Academy of Sciences of the United States of America · 2022Article
- Why do we pick similar mates, or do we?Biology letters · 2021Review
Corrections and comments
- Commented on by
- Commented on by
Authors and funding
4 authors at 4 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The strikingly high incidence of obstructed labor due to the disproportion of fetal size and the mother's pelvic dimensions has puzzled evolutionary scientists for decades. Here we propose that these high rates are a direct consequence of the distinct characteristics of human obstetric selection. Neonatal size relative to the birth-relevant maternal dimensions is highly variable and positively associated with reproductive success until it reaches a critical value, beyond which natural delivery becomes impossible. As a consequence, the symmetric phenotype distribution cannot match the highly asymmetric, cliff-edged fitness distribution well: The optimal phenotype distribution that maximizes population mean fitness entails a fraction of individuals falling beyond the "fitness edge" (i.e., those with fetopelvic disproportion). Using a simple mathematical model, we show that weak directional selection for a large neonate, a narrow pelvic canal, or both is sufficient to account for the considerable incidence of fetopelvic disproportion. Based on this model, we predict that the regular use of Caesarean sections throughout the last decades has led to an evolutionary increase of fetopelvic disproportion rates by 10 to 20%.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.