Glynn Laura M, Davis Elysia Poggi, Schetter Christine Dunkel, Chicz-Demet Aleksandra, Hobel Calvin J, Sandman Curt A
Department of Psychiatry and Human Behavior, University of California, Irvine, CA 92868, USA.
Early Hum Dev. 2007 Oct;83(10):675-81. doi: 10.1016/j.earlhumdev.2007.01.003. Epub 2007 Feb 28.
The implications of the biologically active elements in breast milk for the breastfed infant are largely unknown. Animal models suggest that ingestion of glucocorticoids during the neonatal period influences fear behavior and modifies brain development.
To determine the association between postnatal maternal cortisol levels and temperament in breastfed infants.
The relation between maternal cortisol and infant temperament was examined in breastfed and formula-fed infants. Plasma cortisol was used as a surrogate measure for breast milk cortisol levels (plasma and milk levels are correlated in the 0.6 to 0.7 range; [Patacchioli FR, Cigliana G, Cilumbriello A, Perrone G, Capri O, Alemà GS, et al. Maternal plasma and milk free cortisol during the first 3 days of breast-feeding following spontaneous delivery or elective cesarean section. Gynecologic and Obstetric Investigations 1992;34:159-163.]. If exposure to elevated cortisol levels during infancy influences temperament, then a relation between the two should be found among the breastfed infants, but not among the formula-fed infants.
Two hundred fifty-three two-month-old infants and their mothers.
Fearful temperament assessed with the Infant Behavior Questionnaire [Garstein MR, Rothbart MK. Studying infant temperament via the revised infant behavior questionnaire. Infant Behavior and Development 2003;26:64-86].
Among the breastfed infants, higher maternal cortisol levels were associated with reports of increased infant fear behavior (partial r=0.2; p<0.01). This relation did not exist among the formula-fed infants. Negative maternal affect at the time of assessment did not account for the positive association in the breastfed group.
The findings are consistent with our proposal that exposure to cortisol in breast milk influences infant temperament. Biologically active components in breast milk may represent one avenue through which the mother shapes the development of the human infant during the postnatal period.
母乳中生物活性成分对母乳喂养婴儿的影响在很大程度上尚不清楚。动物模型表明，新生儿期摄入糖皮质激素会影响恐惧行为并改变大脑发育。
确定产后母亲皮质醇水平与母乳喂养婴儿气质之间的关联。
在母乳喂养和配方奶喂养的婴儿中检查母亲皮质醇与婴儿气质之间的关系。血浆皮质醇被用作母乳皮质醇水平的替代指标（血浆和乳汁水平的相关性在0.6至0.7范围内；[Patacchioli FR, Cigliana G, Cilumbriello A, Perrone G, Capri O, Alemà GS等。自然分娩或择期剖宫产后母乳喂养前3天母亲血浆和乳汁游离皮质醇。妇产科研究1992；34：159 - 163。]。如果婴儿期暴露于升高的皮质醇水平会影响气质，那么在母乳喂养的婴儿中应该会发现两者之间的关系，而在配方奶喂养的婴儿中则不会。
253名两个月大的婴儿及其母亲。
使用婴儿行为问卷评估恐惧气质[Garstein MR, Rothbart MK。通过修订的婴儿行为问卷研究婴儿气质。婴儿行为与发展2003；26：64 - 86]。
在母乳喂养的婴儿中，母亲皮质醇水平较高与婴儿恐惧行为增加的报告相关（偏相关系数r = 0.2；p < 0.01）。这种关系在配方奶喂养的婴儿中不存在。评估时母亲的负面情绪并不能解释母乳喂养组中的正相关关系。
这些发现与我们的观点一致，即母乳中皮质醇的暴露会影响婴儿气质。母乳中的生物活性成分可能是母亲在产后塑造人类婴儿发育的一条途径。
