Inclusion criteria:
Be Iranian.• The age of delivery is 18-35 years.• Be literate.• Sign a written consent form.• be primiparous.• Be monotonous.• Show fetal head peak.• The fetal head fits the mother's pelvis.Gestational age is 38 weeks to 42 weeks based on the first day of the last menstrual period or ultrasound of the first trimester of pregnancy.Estimated weight of the fetus using Johnson's law or ultrasound after 32 weeks will be between 25,000 to 4,000 grams.Spontaneous labor has begun (4-5 cm dilatation with at least two contractions of 20 or 30 seconds and more within 10 minutes).• The intensity of labor pain should be greater than 3 on the visual pain scale (10 cm ruler).Do not have speech-auditory or dialect problems that impede communication with the researcher.• Do not have drug and alcohol and tobacco addiction.• Has not had a psychiatric or psychologist experience, medication or hospitalization due to mental illness during the past year.• Has not been under major stress for the past 6 months.• Not be affected by medical conditions.• Do not have midwifery problems.• Has no history of surgery on the uterus or cervix.• Have not used the medicine prescribed by your doctor, midwife or herbal medication for the past 24 hours to start labor pain.• The mother's oral temperature should not be equal to or greater than 38 ° C.• Do not have severe anxiety.• Do not have scars, scratches, burns, eczema or lumbar lesions that prevent heat treatment.
Exclusion criteria:
Mother to discontinue continuing research.Emergency caesarean section is indicated for any reason.Use oxytocin to induce labor or accelerate labor.Use narcotics, Entonox, numbness.• There are signs of fetal distress.• Observe any abnormal cases, such as hypertonic contractions or rapid tibial systolic dysfunction and disturbances in the vital signs of the mother and others• Observe any possible side effects of the infrared belt (skin burns, increased maternal body temperature, abnormal fetal heart sound, abnormal uterine contractions, maternal intolerance to the infrared belt or hot water bag)• Mother's intolerance of infrared belt or hot water bag• Other cases