RELIEVE Study- Platelet-Rich Plasma to Reduce Postpartum Pain After Perineal Tears or Episiotomy

Perineal tears and episiotomies are common after vaginal birth and may cause persistent pain, impaired wound healing, pain during sexual activity, and concerns about genital appearance. Platelet-rich plasma (PRP) is prepared from a participant's own blood and contains a concentrated amount of platelets that release growth factors that may support tissue repair. The purpose of this study is to determine whether a single local injection of autologous non-activated PRP during the primary repair of a perineal tear and/or an episiotomy reduces postpartum perineal pain compared with an injection of 0.9% sodium chloride solution. Participants will be randomly assigned in a 1:1 ratio to receive PRP or saline. Participants, the clinician administering the injection, the clinicians assessing the outcomes, and the statistician will be unaware of the assigned treatment. Follow-up will assess perineal pain, wound healing, scar quality, sexual function, genital self-image, and safety through 6 months postpartum. The study hypothesis is that PRP will reduce average perineal pain at 3 months postpartum compared with saline.

Inclusion Criteria: * Age 18 years or older * Vaginal birth with a second-degree or more severe perineal tear and/or an episiotomy * Written informed consent obtained before any study-specific procedure Exclusion Criteria: * Refusal to participate or lack of decision-making capacity at the time of consent * Inability to ensure an adequately informed consent process despite appropriate support measures, including adapted oral information and, when required, faithful translation or assistance from a professional interpreter * Clinically significant hereditary or acquired coagulation disorder, including platelet count below 100 × 10\^9/L, international normalized ratio above 1.5, activated partial thromboplastin time above 1.5 times the upper limit of normal, congenital coagulation factor deficiency, von Willebrand disease, or prophylactic or therapeutic anticoagulation administered less than 24 hours before venous blood sampling for PRP preparation * Aspirin or clopidogrel taken within 7 days before venous blood sampling for PRP preparation * Previous enrolment in the RELIEVE study