Maternal physical, socioeconomic, and demographic characteristics and childbirth complications in rural lowland Nepal: Applying an evolutionary framework to understand the role of phenotypic plasticity

• Published in: American journal of human biology Vol. 33; no. 6; pp. e23566 - n/a
• Main Authors: Wells, Jonathan C. K., Marphatia, Akanksha A., Cortina‐Borja, Mario, Manandhar, Dharma S., Reid, Alice M., Saville, Naomi
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.11.2021; Wiley Subscription Services, Inc
• Subjects: Adaptation, Physiological; Adolescent; Adolescent Mothers; Adolescents; Adult; Age; Biological evolution; Biomarkers; Body mass; Body mass index; Body size; Body weight; Cesarean Section; Childbirth & labor; Complications; Demographics; Education; Episiotomy; Evolution; Female; Fertility; Humans; Male; Malnutrition; Mothers; Nepal - epidemiology; Nutrition; Nutritional Status; Offspring; Overweight; Parity; Phenotypic plasticity; Pregnancy; Regression analysis; Regression models; Risk; Socioeconomic Factors; Undernutrition; Young Adult; Nepal
• ISSN: 1042-0533; 1520-6300
• DOI: 10.1002/ajhb.23566

Objectives Evolutionary perspectives on human childbirth have primarily focused on characteristics of our species in general, rather than variability within and between contemporary populations. We use an evolutionary framework to explore how physical and demographic characteristics of mothers shape the risks of childbirth complications in rural lowland Nepal, where childbearing typically commences in adolescence and chronic undernutrition is widespread, though maternal overweight is increasing in association with nutrition transition. Methods We conducted secondary analyses of data from a cluster‐randomized trial. Women aged 14–35 years were categorized by age, number of previous pregnancies, height, body mass index (BMI), husband's education, and household wealth. Multivariable logistic regression models tested whether these characteristics independently predicted risks of episiotomy and cesarean section (CS, n = 14 261), and obstructed labor (OL, n = 5185). Results Risks were greatest among first‐time adolescent mothers, though associations with age varied by outcome. Independent of age and parity, short stature and high BMI increased risks of CS and OL, whereas associations were weaker for episiotomy. Male offspring had increased risk of CS and OL but not episiotomy. Wealth was not associated with OL, but lower wealth and lower husband's education were associated with lower likelihood of episiotomy and CS. Conclusions At the individual level, the risk childbirth complications is shaped by trade‐offs between fertility, growth, and survival. Some biological markers of disadvantage (early childbearing, short stature) increased the risk, whereas low socio‐economic status was associated with lower risk, indicating reduced access to relevant facilities. Independent of these associations, maternal age showed complex effects.