Massage Therapy Reduces Stress in Preterm Infants

Preterm infants, born into the specialized environment of Newborn Intensive Care Units (NICUs), often face stress from their surroundings. Since these infants are under-developed, they are born with an immature autonomic nervous system (ANS), which is responsible for controlling and managing stress response and recovery. Factors that cause stress include endless medical procedures, mechanical ventilation, caregiving activities and maternal separation.

In a stressful condition, the ANS over-reacts, and preterm infants fail to process stressors appropriately. In such cases, intervention is a must to enhance the ANS function and maturity.

For the first time, researchers from the University of Louisville School of Nursing have found that massage therapy helps preterm infants reduce stress by promoting ANS development. The study was conducted by researcher Sandra Smith, PhD, of University of Louisville School of Nursing, in collaboration with her team at the University of Utah.

According to the study, published in Early Human Development, massage therapy that consisted of moderate pressure and stroking of the soft tissues followed by flexing and extending the joints of both arms and legs increases the heart rate variability (HRV) in male infants. However, the same was not applicable to female preterm infants.

HRV is a measure of ANS function and development. Infants born at the correct gestational age (term infants) show an increased HRV, whereas preemies (premature infants) display a decreased HRV along with an inability to respond to stressors appropriately. Researchers noticed that male preterm infants showed an increased HRV that was similar to that of the term infants, which supports their ability to respond to various stressors correctly.

Researchers measured HRV during the period of sleep and caregiving in 21 medically stable male and female preterm infants immediately after massage therapy at the end of the second week of study. They noticed no difference in HRV between female preterm infants that had received the massage therapy and those that did not. On the other hand, HRV increased weekly in four male preemies that received massage therapy, but there was no increase in male infants that did not get the massage therapy.

This study suggests that massage therapy enhanced the development of ANS in male preemies, and also improves the infant's response to stressful events.

"We were surprised to learn the differences in the impact of massage therapy on preterm boys and girls," Smith said. "Boys who received massage therapy demonstrated increased heart rate variability, but the therapy did not seem to affect HRV in girls - perhaps there are hormonal reasons for this difference."

In order to clearly understand how massage therapy affects ANS development and to find out the mechanism by which massage therapy promotes ANS function in preterm infants, researchers suggest the need for a future study that will look at a larger sample of preterm infants.