Relaxation interventions can be offered to lactating parents who would like to improve milk supply and increase well-being

By Dr. Liji Thomas, MDMay 9 2024Reviewed by Danielle Ellis, B.Sc.

Human milk is highly beneficial for the normal growth and development of newborns and infants. It also presents a desirable economic profile with an extremely low carbon footprint. Its use is disturbingly low, however, for various reasons, including parental stress and poor mental health. This by itself may predispose to postnatal depression, increasing the risk for lactation failure.

A recent study in JAMA Pediatrics explored the utility of relaxation therapy in increasing milk production in human mothers.

Relaxation therapy

Relaxation therapy is a safe intervention comprising multiple techniques. These include mindfulness, breathing exercises, and meditation, besides intentional relaxation of the muscles in a progressive fashion and music. The aim is to slow the heart rate and respiratory rate, bring down the blood pressure, and induce a feeling of “calmness and wellbeing.”

It could affect milk production via oxytocin and prolactin release, both of which are linked physiologically with stress hormones. Milk letdown could also be responsive to relaxation therapy. In addition, the mother may enjoy better mental health through increased feelings of self-efficacy, which leads to more positive behaviors, including increased feedings or more frequent milk expressions.

There is little evidence to support these postulates, motivating the current study that sought to produce a meta-analysis of the current literature.

About the study

The researchers included 16 studies with a total of ~1,900 participants. This means that 12 new studies and over 1,600 participants were added to the pool, facilitating a fresh meta-analysis.

The studies used a variety of methods, including guided relaxation (six), music (seven), yoga with breathing exercises and, muscle relaxation, and mindfulness. Term infants were included in six studies, and ten included both preterm and early-term infants.

What did the study show?

There was no significant difference at one month of age seen in one study on very preterm infants. It had, however, some missing data and used a sponsor-provided mindfulness app.

At two months, there was no difference, as shown by two studies, one of which was likely to be biased.

Some moderately strong evidence from ten studies indicated higher milk production with relaxation. These were randomized clinical trials (RCTs), where either expressed breast milk (EBM) or milk drunk by a healthy breastfed infant was measured. The latter was measured by test weighing or deuterium isotope.

There was no difference in the milk protein in either arm of three RCTs that covered periods of up to eight weeks. Milk carbohydrates and milk energy showed a small increase from two studies, again covering up to eight weeks. There was no strong evidence of differences in milk fat, milk cortisol, infant head circumference, body composition, or infant behavior.

Infant weight increased but not infant length with the intervention. Maternal anxiety and stress were both reduced, though the effect was small. Some evidence suggested a reduction in the mother’s heart rate and blood pressure.

There was not much evidence to suggest that breastfeeding/milk expression frequency or duration increased, that more colostrum was produced, or that the mother felt more relaxed. Similarly, only low-certainty evidence indicates that the babies cried less or slept more.

Conclusions

There is moderate-certainty evidence that relaxation therapy is linked to the production of more milk in humans. This was accompanied by increased weight gain in infants. Maternal stress and anxiety were slightly decreased.

However, the heterogeneous nature of the included studies makes it difficult to pronounce authoritative conclusions from this meta-analysis. Still, “in the setting of such clinical heterogeneity most analyses were not affected by substantial statistical heterogeneity.” The outcomes may, therefore, be generalized, though the optimal intervention remains debatable.

Future research may focus on objective measures of milk composition and infant growth, as well as on the participants’ experience of relaxation interventions. Trial designs should be optimized to ensure that future studies suffer from less bias.

Again, more effort is required to obtain follow-up data, especially when the time and effort required are higher, such as keeping records of infant behavior and testing the weight of babies fed at the breast.

Despite this, the findings suggest that “relaxation interventions can be offered to all lactating parents” especially given “the lack of major potential harm and high acceptability” of the intervention.