Regev-Sadeh S. et al. - Infrared Light and Photobiomodulation After Episiotomy: A Systematic Review and Meta-Analysis

Among 1,377 patients across 13 studies, infrared radiation reduced pain following an episiotomy (SMD -0.50, 95% CI -0.98 to -0.02) but did not improve healing. Low-intensity laser therapy showed no significant benefit for either pain or wound healing.

What this study measured

An episiotomy leaves a painful perineal wound in the days following childbirth, at a time when mobility and sitting are already limited. Several light-based devices have been proposed to relieve this pain and accelerate healing.

This systematic review and meta-analysis, registered under number PROSPERO CRD42024608543, included 13 randomized and non-randomized studies involving a total of 1,377 patients. The authors deliberately separated the technologies rather than grouping them, which allows for a much more useful interpretation of the results. Three comparisons were analyzed: infrared radiation versus standard care (1,088 patients), low-intensity laser versus placebo (209 patients), and low-intensity laser versus therapeutic ultrasound (80 patients).

Key Findings

The two technologies do not produce the same result, and that is the whole point of this summary.

• Infrarouge contre soins standard, douleur du post-partum : SMD -0,50 (IC 95 % -0,98 à -0,02 ; I² = 88 % ; p < 0,01)
• Infrared therapy, wound healing measurements: no improvement reported
• Low-intensity laser versus placebo, pain: SMD -0.31 (95% CI -0.72 to 0.11; I² = 53%; p = 0.1), not significant
• Low-intensity laser versus placebo, wound healing: SMD 0.23 (95% CI -0.18 to 0.63; I² = 0%; p = 0.85), not statistically significant
• Scope: 13 studies, 1,377 patients

The negative result for low-intensity laser therapy is clear: the confidence intervals cross the zero value for both criteria.

How photobiomodulation works for this indication

The hypothesis is that the drug exerts a local effect on inflammation and fibroblast proliferation, which contributes to the healing of perineal wounds, along with an analgesic effect.

A distinction must be made between the two devices studied here. Infrared radiation primarily delivers heat to the surface, and some of the relief may be attributable to this thermal effect and the comfort it provides, rather than to photobiomodulation in the strict sense. Low-intensity laser therapy, on the other hand, falls squarely within the realm of photobiomodulation, and it is precisely this treatment that shows no benefit.

Limits You Should Know

The negative result for low-intensity laser therapy should be interpreted with caution: only 209 patients were included in this comparison. A lack of statistical significance in a small sample size does not prove the absence of an effect; rather, it indicates that the study does not allow for a definitive conclusion.

For infrared, heterogeneity reaches 88%, and the confidence interval is close to zero, with an upper bound of -0.02. The benefit is therefore statistically significant but fragile. The comparison of laser versus ultrasound, conducted on only 80 patients, shows very high heterogeneity, according to the authors. Finally, the inclusion of non-randomized studies weakens the overall findings.

What This Means in Practice

This review does not support the use of low-intensity laser therapy for pain or wound healing following an episiotomy. This is a negative finding that it would be dishonest to ignore, even though it is based on a small sample size.

Infrared irradiation shows promising results for pain relief, but does not improve wound healing. No serious adverse effects have been reported. The management of postpartum perineal pain remains the responsibility of the obstetric team, which has access to interventions with better-established efficacy.

Frequently Asked Questions

Does low-intensity laser therapy speed up healing after an episiotomy?

No, not in this meta-analysis. The result was an SMD of 0.23 (95% CI -0.18 to 0.63; p = 0.85) compared with placebo—that is, no detectable difference—among 209 patients.

Does infrared therapy relieve pain after childbirth?

The data support this finding, with an SMD of -0.50 (95% CI: -0.98 to -0.02) among 1,088 patients; however, the 88% heterogeneity among the studies makes the estimate somewhat unreliable.

Why do the two devices produce different results?

They do not emit the same energy or the same wavelengths, and infrared radiation has a thermal component that is absent in low-intensity lasers. This study does not allow us to decide between these explanations.

Reference

Regev-Sadeh S, Nahshon C, Cohen N, Lavie O, Zilberlicht A. Efficacy of energy-based devices on episiotomy pain and healing: A systematic review and meta-analysis. International Journal of Gynaecology and Obstetrics, 2025. PMID 41450164. PubMed link

This summary is provided for informational purposes only and does not constitute medical advice. Photobiomodulation is not a substitute for prescribed treatment. Consult a healthcare professional.