Reliability of Lactation Assessment Tools Applied to Overweight and Obese Women

Background: The interrater reliability of lactation assessment tools has not been evaluated in overweight/obese women.

Objective: This study aimed to compare the interrater reliability of 4 lactation assessment tools in this population.

Methods: A convenience sample of 45 women (body mass index > 27.0) was videotaped while breastfeeding (twice daily on days 2, 4, and 7 postpartum). Three International Board Certified Lactation Consultants independently rated each videotaped session using 4 tools (Infant Breastfeeding Assessment Tool [IBFAT], modified LATCH [mLATCH], modified Via Christi [mVC], and Riordan's Tool [RT]). For each day and tool, we evaluated interrater reliability with 1-way repeated-measures analyses of variance, intraclass correlation coefficients (ICCs), and percentage absolute agreement between raters.

Results: Analyses of variance showed significant differences between raters' scores on day 2 (all scales) and day 7 (RT). Intraclass correlation coefficient values reflected good (mLATCH) to excellent reliability (IBFAT, mVC, and RT) on days 2 and 7. All day 4 ICCs reflected good reliability. The ICC for mLATCH was significantly lower than all others on day 2 and was significantly lower than IBFAT (day 7). Percentage absolute interrater agreement for scale components ranged from 31% (day 2: observable swallowing, RT) to 92% (day 7: IBFAT, fixing; and mVC, latch time). Swallowing scores on all scales had the lowest levels of interrater agreement (31%-64%).

Conclusion: We demonstrated differences in the interrater reliability of 4 lactation assessment tools when applied to overweight/obese women, with the lowest values observed on day 4. Swallowing assessment was particularly unreliable. Researchers and clinicians using these scales should be aware of the differences in their psychometric behavior.