The mothers’ breastfeeding behaviour within six weeks postpartum: new scale development and psychometric validation study

Background The evaluation of mothers’ breastfeeding behaviour within 6 weeks postpartum could help health workers comprehensively identify maternal breastfeeding shortcomings, clarify nursing problems, and provide targeted interventions. However, no prior study was found, therefore this study aimed to develop and validate the reliability and validity of the mothers’ breastfeeding behaviour scale within 6 weeks postpartum. Methods A main two-step approach was used: (1) a qualitative pilot study using the purposive sampling method was adopted to test the fitness, simplicity, and clarity of items with 30 mothers; (2) a cross-sectional survey using the convenient sampling method was conducted for item analysis and psychometric validation with 600 mothers. Results The final version of the scale consisted of 36 items with seven dimensions, explaining 68.852% of the total variance. The Cronbach’s α, split-half, and retest coefficients were 0.958, 0.843, and 0.753, respectively. The validity of the scale: (1) Content validity: content validity index (CVI) range of items was between 0.882 and 1.000. The scale-level-CVI was 0.990. (2) Structure validity: The fitting indices were as follows: χ 2 /ⅆ f =2.239, RMR = 0.049, RMSEA = 0.069, TLI = 0.893, CFI = 0.903, IFI = 0.904, PGFI = 0.674, and PNFI = 0.763. (3) Convergent validity: The composite reliability and average variance extracted (AVE) of the seven dimensions were between 0.876 and 0.920 and between 0.594 and 0.696. (4) Distinguish validity: The correlation coefficients were less than the square root of the AVE, except for self-decision behaviour, self-coping behaviour, and self-control behaviour. However, the fit index of the original three-factor model was better than that of the other new models, with significant differences ( P < 0.001). (5) Calibration validity: The area under the curve was 0.860 or 0.898 when the scale was used to predict exclusive or any breastfeeding at 42 days. The correlation coefficients of the maternal breasting feeding evaluation scale, breastfeeding self-efficacy short-form scale, and the scale were 0.569 and 0.674, respectively. Conclusion The newly developed mothers’ breastfeeding behaviour scale within 6 weeks postpartum consists of 36 items belonging to seven dimensions with good reliability and validity and is a reliable and valid instrument to be used in future maternal breastfeeding behaviour assessments and interventions.