Photobiomodulation (PBM), evaluated in this study, will be delivered by a CE marked class IIa medical device (MILTA technology), composed of a panel that gathers 18 emitters. This is an innovative, alternative, soft technology, based on a cross action of LED light emission, a low intensity nanopulsed laser and a magnetic tunnel. The sessions last 10 minutes each, in total in the study two sessions will be delivered.

In a woman's life, maternity is an important stage that is not without consequences, not only in daily life but also in future life. Perineal pain syndrome is a problem frequently encountered in the postpartum period and the review of the literature shows that 95 to 100% of women who have given birth by the vaginal way and who present perineal lesions, suffer from perineal pain at 24 hours of the delivery and approximately 60% of them remain painful at 7 days of the delivery. This incidence can decrease to 42% and 11% respectively in the absence of perineal lesions.

Pain in the postpartum period can not only limit a woman's mobility and affect her quality of life, but can also interfere with the care of her child and thus with the establishment of a good mother-child relationship, and thus prevent her from fulfilling her new role as a mother. Finally, acute pain that is not treated can become chronic and affect long-term physical and psychological health.

Pain management in the immediate postpartum period currently involves the use of level 1 analgesics (paracetamol, NSAIDs), the effectiveness of which is uncertain, and level 2 analgesics (weak morphine derivatives, Acupan, Tramadol), which are more effective for pain, but are sometimes badly tolerated or contraindicated in the case of breastfeeding. Recently, several publications tend to show that alternative solutions would allow a more satisfactory approach to the management of painful patients.

In this study, the investigators propose to evaluate the benefit of an innovative analgesic treatment in the immediate postpartum period using photobiomodulation (PBM) by evaluating pain using a Visual Analog Scale. PBM, discovered in the 1950s, uses the properties of light. The PBM corresponds to all the non-thermal and non-cytotoxic biological effects caused by the exposure of tissues to light sources in the visible and near-infrared range. More precisely, certain wavelengths of the light spectrum (red-infrared) lead to a cascade of biological effects within the cell: reduction of pain, regulation of inflammation and acceleration of the healing process.

The objective of this study is to analyze the possibility of replacing chemical medication by a non-invasive, painless technology in patients who have just given birth. This technology is already used for anti-inflammatory and analgesic actions in indications such as stomatology, rheumatology, post-operation and traumatology. This is part of the field of NMIs (non-medicinal interventions).

Inclusion Criteria:

• Woman aged 18 years or older
• Primi or multiparous patient
• Natural childbirth, regardless of the method of extraction (spontaneous, vacuum, forceps), and damage to the perineum (simple tear, episiotomy, obstetric anal sphincter injury)
• Patients affiliated to a health insurance plan
• Agreeing to participate in the study and having signed an informed consent

Exclusion Criteria:

• Immediate complications related to the childbirth and requiring management in the continuing care unit (delivery haemorrhage, eclampsia, etc.)
• Severe neonatal complications requiring reanimation.
• Patient with a cardiac pacemaker
• Presence of a disease and/or taking photo-sensitising treatment
• Patient under legal protection

The experimental group (real device) and the control 1 group ( fake device) will be in double-blind, neither the investigator nor the patient will know the allocated group.