An interventional study of oral sodium bicarbonate in Labour Dystocia, sponsored by Liz Darling. Not yet recruiting. Open to female participants, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-23.
Sponsored by Liz Darling · Not applicable, Interventional, and Prevention
Sodium bicarbonate is often used by athletes to improve their muscle's ability to contract and power their activity. It works by decreasing the risk of lactic acid build-up, which causes cramping and fatigue. Some research suggests that using sodium bicarbonate in labour could help to improve the ability of the uterus to contract, helping to prevent labour dystocia (stalled or slow progress in labour). This could ultimately increase the chance of spontaneous vaginal delivery. This research is being done to investigate whether drinking sodium bicarbonate (commonly known as baking soda) dissolved in water as a hydration drink could benefit women in labour and increase the chance of a vaginal birth. In order to answer this question, pregnant people from London, Markham and Mississauga midwifery practices are being recruited to participate in this study. Participants will be randomly assigned to one of two groups when they are admitted to hospital in labour. One group will be asked to drink normal fluids of their choice while they are in labour (usual care). The second group will be asked to consume a drink made of baking soda and water, as well as normal fluids of their choice. Mode of birth and the use of birth interventions will be compared between the two groups. Infant outcomes will be compared to ensure that the use this drink in labour is safe. A risk of consuming sodium bicarbonate is gastrointestinal disturbance. The number of people who reported gastrointestinal upset will also be compared between the two groups. If this study shows that those who drank sodium bicarbonate in labour had an increased chance of vaginal birth and that it is safe, this low-cost, low-risk treatment has the potential to reduce birth interventions for pregnant people and their babies.
Sodium bicarbonate is used by athletes to improve muscle contractility and decrease the risk of lactic acid build-up. A moderately sized efficacy study suggests that these proposed effects may be beneficial for nulliparous women in labor to maintain efficiency of labour contractions. Sodium bicarbonate may be useful for improving the contractility of the uterus, helping to prevent labour slowing (dystocia) and ultimately increasing the rate of spontaneous vaginal deliveries. Large scale randomized controlled trials (RCTs) are necessary to determine the effectiveness of sodium bicarbonate for prevention of labour dystocia.
This is an unblinded, open-label, two-arm (treatment vs. usual care control), feasibility RCT evaluating oral sodium bicarbonate for the prevention of labour dystocia for nulliparous midwifery clients at two centres. This study will be conducted with the primary aim of determining feasibility for a full-scale RCT to answer the question: are nulliparous women in midwifery care who receive oral sodium bicarbonate as a hydration drink in labour more or less likely to fail to achieve spontaneous vaginal birth compared to women who drink fluids of their choice? This feasibility study will take place at 4 hospitals in Ontario (Mississauga Hospital, Credit Valley Hospital, Markham Stouffville Hospital, London Health Sciences Centre) and will aim to recruit as many participants as possible during an 8-month period.
55 studies on the registry are indexed under Dystocia; 12 are open to participants now.
This study's planned enrollment of 200 is close to the median of 200 across 42 interventional studies indexed under Dystocia.
Browse Dystocia studies →This is the only study on the registry with Liz Darling as lead sponsor.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Those in the intervention group will be encouraged to sip a solution of sodium bicarbonate (1 imperial teaspoon (\~5g) of sodium bicarbonate dissolved into 250ml of water; if the entire 250mL is consumed, another 1 imperial teaspoon (\~5g) of sodium bicarbonate dissolved in 250mL of water will be provided to the patient) throughout labour with other drinks as desired. All other care will remain the same.
Dietary Supplement: oral sodium bicarbonate
Those in the usual care group will be encouraged to sip fluids of their choice throughout labour as they would normally be encouraged to do. All other care will remain the same.
Those in the oral sodium bicarbonate intervention group will be encouraged to sip a solution of 1 imperial teaspoon (\~5g) of sodium bicarbonate dissolved into 250ml of water throughout labour with other drinks. If the first solution is fully consumed, a second solution will be prepared and offered. Thus, each participant can receive a maximum dose of 2 imperial teaspoons (\~10g) of sodium bicarbonate.
Also known as: Bicarbonate De Soude Usp by Laboratoire Atlas Inc
Feasibility of a full-scale RCT
Feasibility will be determined by assessing recruitment, compliance, participant retention, side effects, completeness of data, participant satisfaction and facilitators and barriers to study implementation.
Time frame: 8 months of recruitment
Failure to achieve a spontaneous vaginal birth
Composite of Caesarean section and assisted vaginal birth
Time frame: At the time of birth
No study locations are listed for this record.
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Oct 2027; primary completion for Dec 2027, 2 months later.
Of 18 interventional studies with no phase under Dystocia, half reached primary completion within 23 months of starting (the median), counting those still running; a quarter within 18 and three quarters within 40. This study's planned 2 months is below that.
Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 23, 2026: start Dec 2025 → Oct 2027, primary completion Dec 2026 → Dec 2027 and completion Dec 2027 → Mar 2028.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Sodium Bicarbonate