Relationships of breast milk intake during one breastfeeding session with sucking time and other determinants: a cross-sectional study.

Abstract

Background: This study explored the correlation between breast milk intake and sucking time during a single breastfeeding session, and analyzed additional factors influencing infant milk intake.

Methods: A cross-sectional survey was conducted from March to July 2024, enrolling 162 mother-infant dyads with infants aged 1 to 12 months. During breastfeeding observations, sucking time was recorded, and milk intake was measured using the test-weighing method. A self-designed questionnaire was used to collect data on maternal and infant health status and feeding practices. Statistical analysis included descriptive statistics (medians and interquartile ranges for non-normally distributed data), non-parametric tests for group comparisons, Pearson correlation, and multiple linear stepwise regression.

Results: Breast milk intake was significantly positively correlated with sucking time (r = 0.57, P < 0.05). The median [IQR] volume of milk intake from the right breast was significantly higher than that from the left breast (60.0 [35.0-85.0] g vs. 48.0 [28.0-70.0] g, P < 0.05). Infants of full-time housewives or mothers on maternity leave exhibited a higher median average milk intake rate than those of working mothers (7.8 [4.5-10.5] g/min vs. 6.5 [3.8-9.0] g/min, P = 0.06). Average milk intake rate was significantly higher in infants aged 5-12 months compared to 1-4 months (median [IQR]: 7.9 [5.0-11.0] g/min vs. 6.5 [3.9-8.8] g/min, P < 0.05). Other factors, including infant sex, overall infant age (when not stratified), birth weight, 24-hour breastfeeding frequency, maternal BMI, parity, maternal age, and maternal occupation (for milk intake volume) showed no significant associations with milk intake volume or intake rate in univariate analyses (all P > 0.05).

Conclusions: Sucking time, current infant body weight, and the breast side used for feeding are key factors influencing breast milk intake during a single breastfeeding session. Further research is warranted to investigate the effects of other factors such as feeding patterns and breastfeeding intervals on milk intake.