Urinary RetentionPhase 4EPIMAGNCT06442995
Evaluation of the Efficacy of the Addition of Magnesium Sulfate to Morphine on the Occurrence of Acute Urinary Retention Following Epidural Anesthesia for Cesarean Section.
A Phase 4 study testing Injection of 500 mg magnesium sulfate + 2 mg morphine into the epidural space and Injection of Isotonic saline + 2 mg morphine into the epidural space in people with Urinary Retention, run by CHU de Reims at 1 site in France.
Trial summary
Peri-medullary anesthesia is the preferred anesthetic technique for Caesarean surgery. Compared with general anesthesia, it reduces maternal and fetal morbidity and mortality, as well as postoperative pain. Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Urinary Retention
- What is being tested?
- Injection of 500 mg magnesium sulfate + 2 mg morphine into the epidural space and Injection of Isotonic saline + 2 mg morphine into the epidural space
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 290 participants
- Where
- 1 siteFrance
- Study dates
- 16 Jan 2025to Dec 2027
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients who have undergone scheduled or emergency Caesarean section surgery under extended epidural anesthesia or combined epidural and spinal anesthesia at the Reims University Hospital.
- Patients who have just undergone caesarean section and have the epidural catheter in place in the post-interventional monitoring room (SSPI).
- Patients who agree to take part in the research and have signed the informed consent form
- Patients of legal age
- Patients affiliated to a social security scheme
Who cannot join
- Minor patients
- Patients protected by law
- Patients allergic to local anesthetics, morphine or magnesium sulfate
- Patients with severe renal insufficiency (GFR < 30 ml/min)
- Patients with pre-pregnancy mictional disorders
- Patients with an American Society of Anesthesiologists (ASA) score of 4
Show all 9Show fewer
- Patients undergoing caesarean section under general anaesthesia, after failure of perimedullary anaesthesia
- Patients with accidental intraoperative injury to the urinary tract
- Patients who have received intravenous magnesium sulfate in the 24 hours preceding cesarean section
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
France1 site, 1 recruiting
- Recruiting
Chu Reims
Reims, 51092
Damien JOLLY, 326788472 ext. 33, djolly@chu-reims.fr
About this study
Official title: Superiority Randomized Double-blind Controlled Trial of Epidural Magnesium Sulfate Addition Versus Placebo on the Occurrence of Acute Post-caesarean Urinary Retention
Peri-medullary anesthesia is the preferred anesthetic technique for Caesarean surgery. Compared with general anesthesia, it reduces maternal and fetal morbidity and mortality, as well as postoperative pain. However, this technique exposes the patient to the adverse effects of peri-medullary morphine, particularly the risk of postoperative urinary retention. Urinary retention during the first 72 hours after Caesarean section affects around 33% of parturients.
This is a particularly debilitating event for parturients, exposing them to the risk of further urinary catheterization, increased theoretical risk of urinary tract infection, traumatic urethral injury, hindered accelerated rehabilitation and altered maternal satisfaction.
Read more
Several studies have demonstrated the benefits of adding magnesium sulfate to epidural anesthesia for Caesarean sections, notably by reducing postoperative pain.
Magnesium sulfate may also have a facilitating effect on postoperative micturition, thanks to its sympathicolytic effect.
This hypothesis is supported by a retrospective study carried out in our maternity hospital, which showed a 15% reduction in post-Caesarean urinary retention when women were given magnesium sulfate in addition to the drugs traditionally used for epidurals.
This little-known property needs to be clarified
Read the detailed description
The main objective of this study is to evaluate the efficacy of the addition of epidural magnesium sulfate in reducing the occurrence of acute post-Caesarean urine retention.
In fact, the incidence of acute urine retention after epidural anaesthesia for Caesarean section is around 33%. Two encouraging studies suggest that adding magnesium sulfate to epidurals could reduce the incidence of acute urine retention by 15%.
This study will be carried out on the obstetric population of the REIMS maternity hospital, starting in summer 2024. It is a randomized, double-blind, placebo-controlled clinical trial. The number of subjects required is calculated at 290 patients, with a power of 80% and an alpha risk of 5%. The statistical hypothesis is that magnesium sulfate reduces the incidence of acute urine retention by 15% compared with placebo (isotonic saline).
Parturients will be informed of the study during a pre-anaesthetic consultation in the 6th month of pregnancy.
Some of these patients will be scheduled for delivery by caesarean section. The remaining patients will be scheduled for a vaginal delivery, which may end up being an emergency caesarean section (10-15% of patients).
After the Caesarean section, patients are taken to the post-procedure monitoring room, where they are monitored for 2 hours.
It is at this point that patients are examined to verify the inclusion and non-inclusion criteria of the protocol. If the inclusion and non-inclusion criteria are met, our teams will provide patients with explanatory documents on our protocol, as well as a consent form for their signature.
When the patient agrees to enter the protocol, the investigators randomize her to one of the following groups:
- Group A: injection of morphine 2 mg into the epidural catheter + magnesium sulfate 500 mg
- Group B: injection of morphine 2 mg into the epidural catheter + isotonic saline.
Group B is the control group. This is the protocol we use in daily practice for parturients who have undergone Caesarean section, in line with the French recommendations of anesthesia societies.
This reduces the parturient's postoperative pain for 20-24 hours. Group A will be the experimental group. Patients will be monitored in the post-natal care unit for 72 hours. The investigators will carry out the same monitoring and care as a parturient outside the protocol. Various data on diuresis, the quantity of urine in the bladder visualized by ultrasound, and the need for urinary catheterization will be recorded.
Statistical analyses will determine whether the incidence of acute urine retention differs between each group.
- Conditions
- Urinary Retention
- Being tested
- Injection of 500 mg magnesium sulfate + 2 mg morphine into the epidural space, Injection of Isotonic saline + 2 mg morphine into the epidural space
- Medical subject headings
- Urinary Retention
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Injection of 500 mg magnesium sulfate + 2 mg morphine into the epidural spaceDrug
When the patient agrees to enter the protocol, the investigators randomize the patient and proceed to the injection of morphine 2 mg into the epidural catheter + magnesium sulfate 500 mg
Injection of Isotonic saline + 2 mg morphine into the epidural spaceDrug
When the patient agrees to enter the protocol, the investigators randomize the patient and proceed to Injection of morphine 2 mg into the epidural catheter + isotonic saline. This is the protocol the investigators use in daily practice for parturients who have undergone Caesarean section, in line with the French recommendations of anesthesia societies
| Study group | Role | What they receive |
|---|---|---|
| Magnesium Sulfate | Experimental | Injection of 500 mg magnesium sulfate + 2 mg morphine into the epidural space Receives: Drug: Injection of 500 mg magnesium sulfate + 2 mg morphine into the epidural space |
| Isotonic saline | Placebo comparator | Injection of Isotonic saline + 2 mg morphine into the epidural space Receives: Drug: Injection of Isotonic saline + 2 mg morphine into the epidural space |
What is being measured
The primary outcome is the main question the study is designed to answer.
diuresis
Measured: 72 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Jun 2024
- Study start16 Jan 2025
- Primary completionJul 2027 (estimated)
- Study completionDec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Urinary RetentionStudies of the same condition, open and under way.
- More trials run by CHU de ReimsThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 290 participants (estimated)
Sponsor and investigators
- Lead sponsor
- CHU de Reims
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06442995
- Sponsor's protocol ID
- PO24038*
- Acronym
- EPIMAG
- Status last verified
- Dec 2025
- First submitted
- 23 May 2024
- Last updated
- 30 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 30 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Superiority Randomized Double-blind Controlled Trial of Epidural Magnesium Sulfate Addition Versus Placebo on the Occurrence of Acute Post-caesarean Urinary Retention
- ClinicalTrials.gov ID
- NCT06442995
- Acronym / sponsor ID
- EPIMAG / PO24038*
- Conditions
- Urinary Retention
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 290 participants (estimated)
- Lead sponsor
- CHU de ReimsUniversity, hospital or other
- Study start
- 16 Jan 2025 (actual)
- Primary completion
- Jul 2027 (estimated)
- Study completion
- Dec 2027 (estimated)
- First posted
- 5 Jun 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Peri-medullary anesthesia is the preferred anesthetic technique for Caesarean surgery. Compared with general anesthesia, it reduces maternal and fetal morbidity and mortality, as well as postoperative pain. However, this technique exposes the patient to the adverse effects of peri-medullary morphine, particularly the risk of postoperative urinary retention. Urinary retention during the first 72 hours after Caesarean section affects around 33% of parturients.
This is a particularly debilitating event for parturients, exposing them to the risk of further urinary catheterization, increased theoretical risk of urinary tract infection, traumatic urethral injury, hindered accelerated rehabilitation and altered maternal satisfaction.
Several studies have demonstrated the benefits of adding magnesium sulfate to epidural anesthesia for Caesarean sections, notably by reducing postoperative pain.
Magnesium sulfate may also have a facilitating effect on postoperative micturition, thanks to its sympathicolytic effect.
This hypothesis is supported by a retrospective study carried out in our maternity hospital, which showed a 15% reduction in post-Caesarean urinary retention when women were given magnesium sulfate in addition to the drugs traditionally used for epidurals.
This little-known property needs to be clarified
Detailed description
The main objective of this study is to evaluate the efficacy of the addition of epidural magnesium sulfate in reducing the occurrence of acute post-Caesarean urine retention.
In fact, the incidence of acute urine retention after epidural anaesthesia for Caesarean section is around 33%. Two encouraging studies suggest that adding magnesium sulfate to epidurals could reduce the incidence of acute urine retention by 15%.
This study will be carried out on the obstetric population of the REIMS maternity hospital, starting in summer 2024. It is a randomized, double-blind, placebo-controlled clinical trial. The number of subjects required is calculated at 290 patients, with a power of 80% and an alpha risk of 5%. The statistical hypothesis is that magnesium sulfate reduces the incidence of acute urine retention by 15% compared with placebo (isotonic saline).
Parturients will be informed of the study during a pre-anaesthetic consultation in the 6th month of pregnancy.
Some of these patients will be scheduled for delivery by caesarean section. The remaining patients will be scheduled for a vaginal delivery, which may end up being an emergency caesarean section (10-15% of patients).
After the Caesarean section, patients are taken to the post-procedure monitoring room, where they are monitored for 2 hours.
It is at this point that patients are examined to verify the inclusion and non-inclusion criteria of the protocol. If the inclusion and non-inclusion criteria are met, our teams will provide patients with explanatory documents on our protocol, as well as a consent form for their signature.
When the patient agrees to enter the protocol, the investigators randomize her to one of the following groups:
- Group A: injection of morphine 2 mg into the epidural catheter + magnesium sulfate 500 mg
- Group B: injection of morphine 2 mg into the epidural catheter + isotonic saline.
Group B is the control group. This is the protocol we use in daily practice for parturients who have undergone Caesarean section, in line with the French recommendations of anesthesia societies.
This reduces the parturient's postoperative pain for 20-24 hours. Group A will be the experimental group. Patients will be monitored in the post-natal care unit for 72 hours. The investigators will carry out the same monitoring and care as a parturient outside the protocol. Various data on diuresis, the quantity of urine in the bladder visualized by ultrasound, and the need for urinary catheterization will be recorded.
Statistical analyses will determine whether the incidence of acute urine retention differs between each group.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Magnesium Sulfate | Experimental | Drug: Injection of 500 mg magnesium sulfate + 2 mg morphine into the epidural spaceInjection of 500 mg magnesium sulfate + 2 mg morphine into the epidural space |
| Isotonic saline | Placebo comparator | Drug: Injection of Isotonic saline + 2 mg morphine into the epidural spaceInjection of Isotonic saline + 2 mg morphine into the epidural space |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Patients who have undergone scheduled or emergency Caesarean section surgery under extended epidural anesthesia or combined epidural and spinal anesthesia at the Reims University Hospital.
- Patients who have just undergone caesarean section and have the epidural catheter in place in the post-interventional monitoring room (SSPI).
- Patients who agree to take part in the research and have signed the informed consent form
- Patients of legal age
- Patients affiliated to a social security scheme
Key exclusion criteria (9 listed)
- Minor patients
- Patients protected by law
- Patients allergic to local anesthetics, morphine or magnesium sulfate
- Patients with severe renal insufficiency (GFR < 30 ml/min)
- Patients with pre-pregnancy mictional disorders
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Injection of 500 mg magnesium sulfate + 2 mg morphine into the epidural spaceWhen the patient agrees to enter the protocol, the investigators randomize the patient and proceed to the injection of morphine 2 mg into the epidural catheter + magnesium sulfate 500 mg | Drug | Magnesium Sulfate |
| Injection of Isotonic saline + 2 mg morphine into the epidural spaceWhen the patient agrees to enter the protocol, the investigators randomize the patient and proceed to Injection of morphine 2 mg into the epidural catheter + isotonic saline. This is the protocol the investigators use in daily practice for parturients who have undergone Caesarean section, in line with the French recommendations of anesthesia societies | Drug | Isotonic saline |
Primary outcome
diuresis
Time frame: 72 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Dec 2025.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Injection of 500 mg magnesium sulfate + 2 mg morphine into the epidural space and Injection of Isotonic saline + 2 mg morphine into the epidural space in people with Urinary Retention, run by CHU de Reims at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 30 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Maxime Riffault (00336 79 63 29 55, mriffault@chu-reims.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
diuresis (time frame: 72 hours). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Dec 2025.