Doctoral Dissertation Improvement: Maternal reproductive trade-offs and the duration of exclusive breastfeeding in a natural fertility population

国际卫生组织建议在婴儿出生后的前6个月内进行纯母乳喂养，以促进婴儿的最佳生长并降低感染疾病的风险。然而，在全球范围内，6个月的纯母乳喂养相对罕见-包括许多传染病发病率高的欠发达人口。对于许多母亲来说，在6个月大之前补充喂养的风险可能并不明显，或者可能被竞争的时间和能量需求所抵消。这项研究将探讨婴儿喂养模式的差异和相关的结果在一个经济边缘化的人口，玻利维亚的Tsimane。这项研究由博士生梅勒妮马丁（加州大学，圣巴巴拉），在博士的监督下。迈克尔Gurven，测试的假设，即母亲的工作和育儿需求减少纯母乳喂养的时间。此外，由于哺乳期的母亲体重迅速减轻，并且不进食，Tsimane母亲可以在6个月大之前引入补充食物，以尽量减少哺乳的热量损失。这种抵消可以使产后体重维持和月经更早恢复。Tsimane妇女无法获得避孕药具;因此，早期补充喂养可能导致Tsimane母亲的高生育率（平均9个孩子）。研究人员将对Tsimane母亲进行调查，以确定纯母乳喂养的时间长短是否因婴儿状况、母亲年龄和状况以及母亲工作和育儿需求而异。研究人员还将前瞻性地收集Tsimane母亲和婴儿的饮食、行为和生物学数据，以研究补充喂养模式如何影响母亲的能量、月经状况、婴儿生长和疾病发生率。这项研究将研究当地的信仰和Tsimane母亲对婴儿健康，生长和发育的看法如何进一步影响喂养决策。研究结果将有助于制定战略，以促进文化上可接受的婴儿喂养做法，最有利于孕产妇和婴儿的健康。

International health organizations recommend exclusive breastfeeding for the first 6 months of life to promote optimal infant growth and reduce risk of infectious illness. Globally, however, exclusive breastfeeding for 6 months is relatively rare - including in many less developed populations with high rates of infectious disease. For many mothers, the risks associated with complementary feeding before 6 months of age may not be apparent, or may be outweighed by competing time and energy demands. This study will examine differences in infant feeding patterns and associated outcomes in an economically marginalized population, the Tsimane of Bolivia.This research by doctoral student Melanie Martin (University of California, Santa Barbara), under the supervision of Dr. Michael Gurven, tests the hypothesis that maternal work and childcare demands reduce the length of exclusive breastfeeding. Furthermore, because nursing mothers rapidly lose weight and do not menstruate, Tsimane mothers may introduce complementary foods before 6 months of age to minimize the caloric losses of nursing. This offset may enable postpartum weight maintenance and earlier resumption of menstruation. Tsimane women do not have access to contraceptives; early complementary feeding may therefore contribute to Tsimane mothers' high fertility rates (average 9 children). The researchers will survey Tsimane mothers to determine if the length of exclusive breastfeeding varies with infant condition, maternal age and condition, and maternal work and childcare demands. Researchers will also prospectively collect dietary, behavioral and biological data from Tsimane mothers and infants to examine how complementary feeding patterns affect maternal energy, menstrual status, infant growth and incidence of illness. The study will examine how local beliefs and Tsimane mothers' perceptions of infant health, growth, and development further influence feeding decisions. Results will aid in devising strategies to promote culturally acceptable infant feeding practices that optimally benefit maternal and infant health.