Market Integration and Reproductive Transitions Among Indigenous Shuar and Neighboring Nonindigenous Ecuadorians in...

Global reproductive transitions are well documented, yet less is known about how neighboring populations with divergent histories and exposure to market integration (MI) experience them. This study examines how sociocultural and economic proxies of MI predict variation in reproductive outcomes among indigenous Shuar and nonindigenous Ecuadorian mestizos (Colonos) from Amazonian Ecuador, focusing on menarcheal age, age at first birth, parity, breastfeeding duration, and contraceptive use.

Reproductive histories were collected from 360 Shuar and 205 Colono women (ages 15-90) between 2008 and 2014. General linear and Poisson regression models were used to assess effects of ethnicity, birth cohort, and MI indices (household-, market-, traditional-style-of-life) on reproductive outcomes; logistic regression determined predictors of contraceptive use.

Shuar women experience earlier age at first birth (p ≤ 0.05) and higher parity (p ≤ 0.001) with little secular change. However, within more market-integrated Shuar households, earlier menarche (p = 0.04), and lower parity (p ≤ 0.001) were documented. By contrast, Colonos show secular increases in age at first birth and declines in parity (both p ≤ 0.05). In both populations, breastfeeding duration decreases over time (p = 0.006) and higher contraceptive use is associated with more market-integrated households (p = 0.03).

Reproductive transitions in Amazonian Ecuador unfold at differing rates, reflecting different histories and degrees of MI. Colonos show clear secular shifts characteristic of reproductive transitions, whereas Shuar show emerging transitions only among more market-integrated households. Results support the context-specific nature of reproductive transitions and highlight value in disaggregated analyses to understand their dynamics.