Efficacy of Breast Milk Olfactory and Gustatory Interventions on Neonates' Biobehavioral Responses to Pain during Heel Prick Procedures

Abstract

This study aimed to evaluate the efficacy of breast milk odor either alone or in combination with breast milk taste (via syringe-feeding) to alleviate neonates' biobehavioral responses to pain during heel-prick procedures. This prospective randomized controlled trial recruited 114 neonates by convenience sampling from a newborn unit of a medical center in Taiwan. Neonates were randomly assigned to three groups: control (gentle touch + human voice), control + breast milk odor, and control + breast milk odor + breast milk taste. Heart rate, oxygen saturation, and voice recordings of crying were measured across heel-prick procedures: baseline, no stimuli (stage 0); during heel prick (Stages 1-4); and recovery (Stages 5-10). Generalized estimating equations and Kaplan-Meier survival analysis compared differences in changes between groups for heart rate, oxygen saturation, and time to crying cessation. Changes in mean heart rate and oxygen saturation in neonates receiving breast milk odor or breast milk odor + breast milk taste were significantly less than those at the corresponding stage for the control group. Among neonates receiving breast milk odor or breast milk odor + breast milk taste, hazard rate ratios for crying cessation were 3.016 and 6.466, respectively. Mother's breast milk olfactory and gustatory interventions could stabilize the biobehavioral responses to pain during heel prick procedures in neonates.

Keywords: biobehavioral response; breast milk odor and taste; heel prick; neonates; olfactory and gustatory interventions; pain; syringe feeding.

Figure 1

Flowchart of participant recruitment for the three treatment interventions. GT, gentle touch + human voice = control condition; BM, breast milk; BMTSF, breast milk taste by syringe feeding.

Figure 2

Heel-prick stages (1 min for each stage).

Figure 3

Clustered error-bar graph showing time trends of mean heart rates with 95% confidence intervals (CI) for neonates in the three treatment groups over heel-prick stages. Groups: 1 (blue), gentle touch plus human voice (control condition); 2 (green), control condition + breast milk odor; 3 (red), control condition + breast milk odor + breast milk taste by syringe feeding; Stage 0, baseline (no stimulation); Stages 1 to 4, the 1st to the 4th min during heel prick, respectively; Stages 5 to 10, the 1st to 6th min after completion of heel prick, respectively.

Figure 4

Clustered error-bar graphs showing time trends of mean oxygen saturation (SpO₂) with 95% confidence intervals (CI) for neonates in the three treatment groups over heel-prick stages. Groups: 1 (blue), gentle touch plus human voice (control condition); 2 (green), control condition + breast milk odor; 3 (red), control condition + breast milk odor + breast milk taste by syringe feeding; Stage 0, baseline (no stimulation); Stages 1 to 4, the 1st to the 4th min during heel prick, respectively; Stages 5 to 10, the 1st to 6th min after completion of heel prick, respectively.

Figure 5

Kaplan–Meier survival analysis comparing the accumulated rate of time to cessation of crying during heel-prick procedures for neonates in the three treatment groups. Groups: 1 (blue), gentle touch plus human voice (control condition); 2 (green), control condition + breast milk odor; 3 (pink), control condition + breast milk odor + breast milk taste by syringe feeding.