Background: Pain during labor can be a barrier when choosing vaginal delivery. In an attempt to relief pain during labor, several pharmacological and nonpharmacological methods are proposed. Objective: To assess the effect of light-emitting diode (LED) photobiomodulation on analgesia during labor. Methods: A clinical trial was conducted with 29 women who were divided into two groups: G1 (experimental group-LED) and G2 (control group-hot shower). In the experimental group, an LED plate with red and infrared merged [red 660 ± 20 nm, 5 mW/cm2, 3 J per LED (108 J) and infrared 850 ± 20 nm, 5 mW/cm2, 3 J per LED (108 J), total energy = 216 J] was placed on the subjects' dorsal region, at the level of T10 to S4, for 10 min, with the plate automatically turning off. Hot shower at controlled temperature was offered for 30 min. To verify the effect of LED on analgesia during labor, the following variables were assessed: (1) perception of pain, (2) fetal well-being assessed by cardiotocography or intermittent auscultation of fetal heart rate, (3) Apgar score at minutes 1 and 5 after birth, and (4) labor duration. Results: There was a statistically significant difference (p < 0.05) in pain reduction evidenced by a millimetric visual scale, before and after application on G1-LED (7.92 ± 1.78). Regarding the other variables, there was no statistical difference between the groups when comparing fetal well-being, Apgar score and labor duration. Conclusions: It is concluded that LED can be considered an alternative, since it caused pain reduction without changing other parameters during labor, compared with hot shower, a method included in hospital protocols, proving to be safe. Clinical Trial Registration number: NCT03496857.
Keywords: analgesia; childbirth; light-emitting diode; phototherapy.