Relaxation Therapy and Human Milk Feeding Outcomes: A Systematic Review and Meta-Analysis

Abstract

Importance: Human milk feeding is a key public health goal to optimize infant and maternal/parental health, but global lactation outcomes do not meet recommended duration and exclusivity. There are connections between lactation and mental health.

Objective: To appraise all available evidence on whether the provision of relaxation interventions to lactating individuals improves lactation and well-being.

Data sources: Embase, MEDLINE, CINAHL, Allied and Complementary Medicine Database, Web of Science, and the Cochrane Library were searched on September 30, 2023, and topic experts were consulted.

Study selection: Two independent reviewers screened for eligibility. Inclusion criteria were full-text, peer-reviewed publications with a randomized clinical trial design. Techniques that were entirely physical (eg, massage) were excluded. A total of 7% of initially identified studies met selection criteria.

Data extraction and synthesis: Two independent reviewers extracted data and assessed risk of bias with the Cochrane Risk of Bias 2 tool. Fixed-effects meta-analysis and Grading of Recommendations, Assessment, Development, and Evaluations guidelines were used to synthesize and present evidence.

Main outcomes and measures: Prespecified primary outcomes were human milk quantity, length and exclusivity of human milk feeding, milk macronutrients/cortisol, and infant growth and behavior.

Results: A total of 16 studies were included with 1871 participants (pooled mean [SD] age for 1656 participants, 29.6 [6.1] years). Interventions were music, guided relaxation, mindfulness, and breathing exercises/muscle relaxation. Provision of relaxation was not associated with a change in human milk protein (mean difference [MD], 0 g/100 mL; 95% CI, 0; 205 participants). Provision of relaxation was associated with an increase in human milk quantity (standardized mean difference [SMD], 0.73; 95% CI, 0.57-0.89; 464 participants), increased infant weight gain in breastfeeding infants (MD, z score change = 0.51; 95% CI, 0.30-0.72; 226 participants), and a slight reduction in stress and anxiety (SMD stress score, -0.49; 95% CI, -0.70 to -0.27; 355 participants; SMD anxiety score, -0.45; 95% CI, -0.67 to -0.22; 410 participants).

Conclusions and relevance: Results of this systematic review and meta-analysis suggest that provision of relaxation was associated with an increase in human milk quantity and infant weight gain and a slight reduction in stress and anxiety. Relaxation interventions can be offered to lactating parents who would like to increase well-being and improve milk supply or, where directly breastfeeding, increase infant weight gain.

Figure 1.. Cochrane Risk of Bias 2 Score for Overall Outcome and Each Domain

DS indicates domain S (period and carryover, crossover studies only); D1, domain 1 (randomization); D2, domain 2 (deviations from intended interventions); D3, domain 3 (missing outcome data); D4, domain 4 (outcome measurement); D5, domain 5 (result selection).

Figure 2.. Summary of Meta-Analysis Results

BP indicates blood pressure; MD indicates mean difference; RR, relative risk; SDS, standard deviation score; SMD, standardized mean difference; VAS, Visual Assessment Scale. ^aIndicates significant results (P < .05); arrow shows direction of effect. ^bMeasurements were taken using the Breastfeeding Self-Efficacy Scale (short form for the neonatal intensive care unit).

Figure 3.. Forest Plots for Human Milk Quantity, Protein, Carbohydrate, and Energy

Each forest plot is grouped by risk of bias assessment. MD indicates mean difference; SMD, standardized mean difference.

Figure 4.. Forest Plots for Infant Weight and Length Gain, Maternal/Parental Anxiety, and Stress

Each forest plot is grouped by risk of bias assessment. MD indicates mean difference; SDS, standard deviation score; SMD, standardized mean difference.