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Secular changes in body height predict global rates of caesarean section
Eva Zaffarini1,2, Philipp Mitteroecker1
11 Department of Theoretical Biology, University of Vienna , Althanstrasse 14, 1090 Vienna , Austria.
Proceedings. Biological Sciences
|April 10, 2019
Summary
Global caesarean-section (C-section) rates are linked to rising adult body height trends. Improved living conditions lead to larger fetuses, increasing obstructed labor risk and C-section rates.
Area of Science:
- Global Health
- Human Biology
- Obstetrics
Background:
- Caesarean-section (C-section) rates vary significantly worldwide.
- Existing explanations include socio-economic, medical, and cultural factors.
Purpose of the Study:
- To investigate the impact of adult body height trends on global C-section rates.
- To explore the relationship between socio-economic development, body size, and childbirth outcomes.
Main Methods:
- Analysis of global C-section rate variance.
- Utilizing a structural equation model to assess causal pathways.
- Examining trends in adult body height from the 1970s to the 1990s.
Main Results:
- Adult body height trends explain one-third of the global variance in C-section rates.
- Improved living conditions correlate with increased maternal and fetal body size.
- Disproportionately large fetuses due to intergenerational growth differences increase obstructed labor risk.
Conclusions:
- Historical socio-economic development influences childbirth difficulty through effects on growth and maternal-fetal dimensions.
- Body height changes represent a significant, direct factor affecting C-section rates.
- Findings challenge the concept of a universal 'ideal' C-section rate suggested by the World Health Organization (WHO).
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