[Breast milk intake of Chinese infants aged 0-5 months in 2019-2021]

To describe the breast milk intake of infants aged 0-5 months in China and its trends, and to analyze the effects of feeding mode, gender and regions on breast milk intake.

Data were extracted from Ministry of Science and Technology's basic resource survey project "China's 0-18-year-old children's nutrition and health system survey and application" project. Caregivers were face to face interviewed to collect the basic information of infants. Weighing method was used to measure 24 hourly breast milk intake of infants aged 0-5 months in China. The rank sum test was used to compare the differences in breast milk intake between groups, the Spearman rank sum test was used to analyze the trend of breast milk intake with increasing age, and the general linear regression model was used to analyze the effects of gender and region on breast milk intake.

The mean breast milk intake of exclusively breastfed infants aged 0-5 months was 800.1 g/d, ranging from 696.4 to 937.7 g/d. Breast milk intake increased with age and remained stable at 5 months(β=29.6, P=0.009). There was a statistically significant difference in breast milk intake among infants in different month age groups(χ~2=17.96, P=0.003). Infants aged 0-5 months who are exclusively breastfed were fed 8 times in 24 hours, the breast milk intake per each time is 103.4-152.5 g, the duration of each feeding is 20.4-24.6 min, and the breast milk intake per minute is 4.4-7.0 g. Except for 5 months of age, there was no gender difference in the 24-hour breast milk intake of exclusively breastfed infants aged 0 to 4 months(P>0.05). Except for 4-month-old exclusively breastfed infants, there was no regional differences in the breast milk intake of others(t=-4.25, P<0.001). In the mixed feeding group, breast milk + complementary feeding group and breast milk + formula powder + complementary feeding group, the breast milk intake of infants aged 0-5 months were 341.1-496.7 g, 239.1-742.7 g and 90.0-508.0 g, respectively.

In 2019-2021, infants aged 0-5 months in China Breast milk intake increased with age, and remained stable at 5 months. The breast milk intake of infants aged 0-5 months in different regions or genders is similar except for individual months. The introduction of formula or complementary food directly affects the intake of breast milk in infants.