AimFew studies investigate factors that might influence the content of expressed breastmilk. This study aims to investigate the influence of the intervals between breastmilk pumping and the time of the day on protein and fat concentration in breastmilk.MethodsMothers of very preterm infants in a neonatal ward who expressed more than 400 mL per day were included. Expressed breastmilk was obtained from each mother over 30 h who were pumping at strictly planned and varying intervals: 2, 3, 4 and 6 h. All samples were analysed using infrared transmission spectroscopy.ResultsTen mothers participated at a median of 22 days postpartum. A total of 176 milk samples were analysed, and the average protein and fat concentrations in g/100 mL were 1.1 ± 0.23 and 4.2 ± 1.3, respectively. The time intervals between breast pumping sessions did not impact protein content, but fat content decreased by longer intervals (p < 0.01). The time of the day for milk pumping did not influence the protein or fat content.ConclusionA single milk sample collected after any 2–6 h interval, at any time during the day, represents the protein content in the breastmilk, but not the fat content which decreased with longer intervals.

中文翻译：

---

吸奶之间的时间间隔不会影响早产儿母亲产生的母乳蛋白质

目的 很少有研究调查可能影响挤出的母乳含量的因素。本研究旨在探讨吸乳时间间隔和一天中的时间对母乳中蛋白质和脂肪浓度的影响。方法纳入新生儿病房每天吸奶量超过400 mL的极早产儿的母亲。每位母亲在 30 小时内以严格计划的不同间隔（2、3、4 和 6 小时）吸奶，获得了挤出的母乳。所有样本均使用红外透射光谱进行分析。结果 10 名母亲参与的时间平均为产后 22 天。总共分析了 176 个牛奶样品，平均蛋白质和脂肪浓度（g/100 mL）分别为 1.1 ± 0.23 和 4.2 ± 1.3。吸奶时间间隔不会影响蛋白质含量，但脂肪含量会随着时间间隔的延长而降低（p< 0.01）。一天中吸奶的时间不会影响蛋白质或脂肪含量。结论 在一天中的任何时间，在任何 2-6 小时间隔后收集的单一乳汁样本代表母乳中的蛋白质含量，但不代表脂肪含量随着时间间隔的延长而减少。