The goal of this clinical trial is to determine if topical application of compresses soaked in 25% magnesium sulfate on painful perineum after birth is effective to alleviate pain.

Researchers will compare this treatment to a placebo, compresses soaked in water. Participants will be invited to use their compresses if needed, for 15 minutes, up to four times a day, during their stay at the hospital after giving birth. They will also have to keep a diary of their usage and of their pain.

Background: Despite the high frequency of perineal trauma in obstetrics, management of perineal care and pain is highly variable, relying on very few studies, if any. Treatment of the perineum with compresses soaked in a magnesium sulfate (Epsom salt) solution has not previously been studied but is routinely used in some hospitals in Quebec, Canada. Objectives: This study aims to determine whether compresses soaked in 25% magnesium sulfate in sterile water can alleviate perineal pain in women immediately after childbirth. Population and intervention: Women who have just given birth vaginally and report perineal or vulvar pain of 3/10 or more will be recruited and randomized into an intervention group receiving the treatment (compresses soaked in 25% magnesium sulfate) or a control group receiving a placebo (compresses soaked in water). Methods: This multi-centric, double-blinded randomized clinical trial will be conducted in four hospitals in the province of Quebec, Canada. The investigators plan to recruit a total of 104 participants. Participants will be instructed to apply the compresses on the vulva and perineum for 15 minutes, four times per day, if needed. They will be asked to score their pain before and after using the compresses for the length of their hospital stay, typically between 24 and 48 hours. Secondary outcomes include analgesic use, incidence of complications, participant satisfaction, opinions on feasibility, and any adverse effects caused by the compresses. Discussion: This randomized controlled trial will assess whether the treatment is more effective in relieving pain than the placebo. The study will also determine the safety and feasibility of this method for routine postnatal care. This study could contribute in the long term to the standardization of evidence-based practices for the management of postpartum perineal pain in Canadian hospitals

Inclusion Criteria:

• Planned hospital stay at the mother-child unit of the Hôpital de Chicoutimi, Hôpital Charles-Le Moyne, or Hôpital Honoré-Mercier
• Vaginal delivery with or without perineal tear, any degree of tear, including episiotomies
• Obtaining consent for the study
• Languages spoken: French, English or both

Exclusion Criteria:

• Hemodynamic instability
• Surgical procedure such as a cesarean section
• Transfer to another hospital
• Transfer to another care unit
• Chronic use of narcotics
• Inability to complete the logbook
• Unsigned consent form

Person who has given birth vaginally

This study is a triple-blind study. Parturients will be instructed to apply soaked pads (SSE25 or sterile water) for 15 minutes, as needed, four times a day to the perineum, regardless of which group they are in. They will not know the compound in their bottle, they will only know the number of their bottle. The nurses who distribute the bottles to the patients on their shifts will not know which bottle is sterile water and which is SES.25 In addition, each container will be identical and each liquid will have the same texture and color, making it impossible to identify the contents. As described above, the hospital pharmacy will be responsible for preparing bottles and the pharmacy employees will be the only ones who know the contents. Finally, during data analysis, there will be denominationalization of patients and remittance of data that will not be associated with specific intervention groups, so that data analysis will also be blinded.