Related Experiment Video
Updated: Feb 20, 2026
04:08
Mouse Model of Surgical Uterine Injury and Subsequent Pregnancy Outcomes
Published on: June 27, 2025
1.2K
Cliff-edge model predicts intergenerational predisposition to dystocia and Caesarean delivery
Philipp Mitteroecker1, Sonja Windhager2,3, Mihaela Pavlicev4
1Department of Theoretical Biology, University of Vienna, A-1090 Vienna, Austria; philipp.mitteroecker@univie.ac.at.
Summary
Caesarean sections may be increasing fetal size, leading to more difficult childbirths (fetopelvic disproportion). Women born via Caesarean delivery are more likely to experience fetopelvic disproportion themselves, supporting the cliff-edge evolutionary model.
Area of Science:
- Human evolution
- Reproductive biology
- Medical anthropology
Background:
- The cliff-edge model proposes that increased Caesarean sections since the mid-20th century have driven evolutionary increases in fetal size relative to maternal pelvic dimensions.
- This evolutionary pressure is hypothesized to increase incidences of fetopelvic disproportion (FPD).
Purpose of the Study:
- To test the cliff-edge model's prediction of intergenerational predisposition to FPD.
- To evaluate if women born via Caesarean delivery for FPD are at higher risk for FPD in their own childbirth.
Main Methods:
- Analysis of multigenerational epidemiological data on childbirth outcomes.
- Comparison of Caesarean delivery risks between women born via Caesarean versus vaginally, specifically for anatomical indications of FPD.
Main Results:
- Multigenerational studies show an intergenerational predisposition to surgical delivery.
- Women born by Caesarean delivery for FPD face up to twice the risk of Caesarean delivery compared to women born vaginally.
- The study's model predicts a 2.8-fold increased risk of FPD for mothers born by Caesarean due to FPD.
Conclusions:
- Findings support the cliff-edge model of obstetric selection and its assumptions.
- The intergenerational link between Caesarean delivery for FPD and subsequent risk provides evidence for evolutionary pressures on human childbirth.
- Despite idealizations, the model's congruence with epidemiological data strengthens its validity.
More Related Videos
Related Concept Videos
01:21Nondisjunction
5.2K
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers. Nondisjunction is common during anaphase I or anaphase II of meiosis. Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold...
5.2K
01:35Pedigree Analysis
89.9K
Overview
89.9K
02:30Genomic Imprinting and Inheritance
37.4K
Diploid organisms inherit genetic material through chromosomes from both parents. Copies of the same gene are known as alleles. In most cases, both alleles are simultaneously expressed and allow various cellular processes to function optimally. If one of the alleles is missing or mutated, the expression of the other allele can compensate; however, this is not true for all genes.
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
37.4K
01:43Incomplete Dominance
30.4K
Gregor Mendel's work (1822 - 1884) was primarily focused on pea plants. Through his initial experiments, he determined that every gene in a diploid cell has two variants called alleles inherited from each parent. He suggested that amongst these two alleles, one allele is dominant in character and the other recessive. The combination of alleles determines the phenotype of a gene in an organism.
30.4K
01:09Preparedness and Phobias
371
Human fear responses to certain stimuli, such as darkness, heights, deep water, and blood, can often arise despite the absence of direct negative experiences. This phenomenon is rooted in evolutionary psychology, which posits that humans have developed a predisposition to fear stimuli that historically posed significant survival threats. This predisposition, known as preparedness, suggests that early humans who developed a fear of potentially dangerous entities, such as venomous snakes and...
371
01:52Regression Toward the Mean
7.2K
Regression toward the mean (“RTM”) is a phenomenon in which extremely high or low values—for example, and individual’s blood pressure at a particular moment—appear closer to a group’s average upon remeasuring. Although this statistical peculiarity is the result of random error and chance, it has been problematic across various medical, scientific, financial and psychological applications. In particular, RTM, if not taken into account, can interfere when...
7.2K