Review question

We investigated how well breastfeeding or supplemental breast milk (expressed breast milk given via feeding tube or by placing breast milk in baby's mouth) works as a pain reliever in newborn babies while they undergo painful procedures (e.g. vaccination, heel prick, blood sampling for tests or eye examinations). The babies' pain responses (e.g. changes in heart rate, oxygen level, blood pressure, percentages of crying time, duration of crying etc.) were assessed by health care professionals to measure the pain that babies are experiencing.

Background

Breastfeeding may provide pain relief for newborn babies undergoing painful procedures. Medication for pain relief is commonly given for major painful procedures, but may not be given for minor painful procedures such as blood sampling (by heel prick or taking a sample from a vein). There are different forms of non-drug strategies that can be used to reduce pain in babies, such as holding or swaddling them, sucking on a pacifier, or giving sweet solutions (such as sucrose or glucose). Different studies done in newborn babies have shown that breastfeeding may be a good way to reduce the pain they feel when subjected to minor painful procedures. These studies have been done in full-term babies, and they have shown that breastfeeding may be effective by demonstrating that it reduces babies' crying time and various pain scores that have been validated for babies. Breast milk given by syringe has not shown the same efficacy as breastfeeding itself. Very few studies have been done in preterm babies, and so new studies are needed to determine if the use of supplemental breast milk in these small babies is effective in reducing their pain.

Study characteristics

We searched the medical literature thoroughly up to 1 August 2022 for studies that investigated the pain-relieving effect of breastfeeding or supplemental breast milk for minor medical procedures in newborn full-term and preterm neonates We included randomised trials only, as they provide the most reliable medical evidence. We identified 66 studies that reported on a total of more than 6200 infants in this Cochrane Review. Thirty-six studies evaluated breastfeeding, 29 studies evaluated supplemental breast milk, while one study compared both against each other. In over half of the studies, pain relief was during a heel prick procedure. In others, it was during vaccination, drawing blood from a vein or other procedures. The studies used a variety of comparative groups, for example, placebo, no intervention, maternal holding, skin-to-skin contact, similar volume of water, a pacifier, routine care, various concentrations of sucrose or glucose, 'facilitated tucking' (holding the infant in a flexed position with arms close to the body and hands placed to promote sucking), swaddling, heel warmth, anaesthetic cream for the skin, or a combination of these. The studies used a wide variety of pain scales as well as changes in heart rate and blood pressure and cry duration to assess pain.

Study funding sources

The studies included in the review were not externally funded according to information given in the reports.

Key results

Newborn babies in the breastfeeding group experienced a lower heart rate, shorter duration of cry, lower percentage of cry time and lower scores on the Neonatal Infant Pain Scale than babies who received no intervention. Moderate concentrations of glucose/sucrose may have similar effectiveness to breastfeeding. Studies of supplemental breast milk showed variable results. Supplemental breast milk was found to have a lower increase in heart rate when compared to water, and a lower duration of crying when compared to placebo.

What are the limitations of the evidence

We are moderately confident that breastfeeding reduces pain as assessed by heart rate, cry duration or validated pain scale compared to no intervention. Supplemental breast milk for painful procedures may reduce pain when compared to no intervention or placebo.

Due to the high number of comparator groups, other measures of pain were assessed in a very small number of studies. The majority of the studies did not report on any unwanted or harmful effects of treatment. Those that did this identified no unwanted or harmful effects of treatment in any infants.