RESEARCH POSTER PRESENTATION DESIGN © 2019
www.PosterPresentations.com
This research project looks at the causes of
adverse pregnancy and birth outcomes in the
U.S. to investigate dominant perspectives on
the evolutionary implications of bipedalism for
risk in childbirth, and increased risk
associated with adolescent pregnancy
compared to adult pregnancy. The Obstetrical
Dilemma posits that bipedalism and
increasing brain size in our evolutionary
history led to increased risk of obstructed
labour. However, causes of maternal mortality
are not only, or even predominantly, related to
pelvic morphology (i.e., cephalopelvic
disproportion during labour). Rather there are
multiple “obstetrical dilemmas” or factors that
may cause complications in childbirth, many
of which may be preventable. Data have been
collected from the U.S. Centers for Disease
Control National Vital Statistics to critically
analyze pregnancy and birth outcomes in
women, sorted by maternal age and single
race. This project aims to provide a better
understanding of why maternal and infant
mortality occurs during or soon after
childbirth, the role of pelvic physiology in an
evolutionary sense (i.e., did childbirth become
exponentially more dangerous and difficult
alongside the evolution of bipedalism?), the
impact of immature pelvic growth on
adolescent pregnancies, and why certain
groups of women experience significantly
higher risk of maternal mortality and adverse
pregnancy outcomes than others.
OBJECTIVES
Homo sapiens experience a difficult and dangerous childbirth compared to non-human primates and
other mammals. The Obstetrical Dilemma is a long-standing hypothesis that human infants are born
relatively early due to a narrow female pelvis as a result of bipedalism (Dunsworth 2018). However, recent research aims to dismantle this theory from several angles. Maternal and infant mortality in the U.S. and Global North is not commonly associated with cephalopelvic disproportion. Rather than
focusing on evolutionary complications associated with childbirth, a public health focus could be more beneficial for reducing maternal and infant mortality rates in the U.S. Particular groups of women
experience much higher rates of maternal mortality and adverse pregnancy outcomes in the U.S. This project aims to understand the racial disparities in maternal and infant mortality rates as well as the biological impact of immature pelvic growth on adolescent pregnancy.
MATERIALS AND METHODS
RESULTS CONCLUSION
Though humans do experience a relatively difficult childbirth, the root of the problem is not an
evolutionary obstetrical dilemma but rather a
collection of contemporary health and systemic issues. The multiple “obstetrical dilemmas”
contributing to disparities in rates have more to do
with maternal age and access to health care than the bipedal pelvis. Certain groups of women in the U.S. experience disproportionately high rates of maternal mortality, infant mortality, and adverse pregnancy
outcomes. These risks are heightened in adolescent pregnancies. In Canada, data are not collected using the same methods as the U.S. CDC as we do not
record racialized identities. Though this is an
important aspect of Canadian public health, it does
make it difficult to analyze disparities between groups of women in Canada who may experience
disproportionately higher risk than others. The
patterns found in this project are likely similar to what would be seen in Canada, were the data available.
Lastly, further research must be done to fully understand the role of sociocultural factors in biological risk in pregnancy.
REFERENCES
Dunsworth, H. 2018. There is No “Obstetrical Dilemma”: Towards a Braver Medicine with Fewer Childbirth Interventions.” Perspectives in Biology and Medicine 61(2): 249-63.
United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics (DVS). Fetal Deaths 2005-2017, as compiled from data
provided by the 57 vital statistics jurisdictions through the Vital Statistics Cooperative Program, on CDC WONDER Online Database. http://wonder.cdc.gov/fetal-deaths-expanded-current.html
United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics, Natality public-use data 2016-2018, on CDC WONDER Online Database, September 2019.
http://wonder.cdc.gov/natality-expanded-current.html
Wikimedia Commons. 2015. File: A Visual Comparison of the Pelvis and Bony Birth Canal Vs. the Size of Infant Skull in Primate Species. https://bit.ly/3cmctsh
World Health Organization (WHO). 2019. Maternal Mortality.
http://www.who.int/news-room/fact-sheets/detail/maternal-mortality
ACKNOWLEDGEMENTS
Please note that the U.S. CDC data are collected using racialized identities. I have used these data to highlight disparities between groups of women in the U.S., not to support sociocultural racialized identities as a form of dividing persons based on their skin colour. I would like to acknowledge and thank Dr. Helen Kurki for her
assistance and support in the completion of this project.
For this project, I have used the U.S. Centers for
Disease Control and Prevention (CDC) public health data on infant deaths and births. These data are
sorted by maternal age (<15-19 years, 20-34 years, and 35-44 years). To understand racial disparities in the U.S., data are also divided into three maternal single race categories: Black or African American,
American Indian or Alaska Native, and White. This is to highlight the higher risks associated with particular groups of women in the United States. I have
produced graphs to visualize these data and show trends across the country between age groups and racialized identities. One-way ANOVAs and Tukey post-hoc tests have been conducted to compare the mean obstetrician estimated (OE) gestational age and birth weight between age groups and maternal single race. The resulting p-values from the Tukey post-hoc tests are displayed in tables. A p-value ≤
0.05 is statistically significant and indicates a difference in means between groups.
Maternal mortality: Inevitable evolutionary obstetrical dilemma
or preventable health outcome?
Emma Ronayne, Department of Anthropology
March 4, 2020
This research was supported by the Jamie
Cassels Undergraduate Research Awards,
University of Victoria
Supervised by Dr. Helen Kurki
0 2 4 6 8 10 12 14 16 18
<15-19 years 20-34 years 35-44 years
Inf ant mor tality rate per 1 000 li ve bi rt hs Maternal age
2017 infant mortality rates per 1000 live births by maternal age and single race
Black or African American American Indian or Alaska Native White
Table 1. Tukey HSD post-hoc test p-values for average OE gestational age and average birth weight in adolescents under 15 years of age
between racial groups.
Groups for comparison p-value
Average OE gestational age
Average birth weight
Native American or Alaska Native vs. Black or African American
0.087 0.087
Native American or Alaska Native vs. White
0.419 0.503
Black or African American vs. White 0.005 <0.001
10.54 8.63 4.83 BLACK OR AFRICAN AMERICAN AMERICAN INDIAN OR ALASKA NATIVE WHITE Inf ant mor tality rate per 1 000 li ve bi rt hs
2017 infant mortality rate by maternal single race
37.6 37.7 37.8 37.9 38 38.1 38.2 38.3 38.4 38.5 38.6
<15-19 years 20-34 years 35-44 years
OE gestat io nal age ( we eks) Maternal age
OE gestational age by maternal age and single race
