Calcium Carbonate on Labor Induction

The Effect of Calcium Carbonate on Labor Induction: A Pilot Study

The investigators aim to evaluate the safety and efficacy of administering calcium carbonate to laboring participants undergoing labor inductions. The investigators hypothesize that calcium carbonate is a low-risk preventative measure to decrease oxytocin induction time and dosage, decrease the rate of labor dystocia, decrease the rate of cesarean deliveries, and demonstrate no differences in maternal or neonatal safety outcomes.

Study Overview

• Status: Active, not recruiting
• Conditions: Pregnancy; Uterine Contraction
• Intervention / Treatment: Dietary supplement: Calcium Carbonate

Detailed Description

The investigators plan to assess (1) duration of induction with oxytocin administration, (2) rate of labor dystocia/failed induction, (3) rate of cesarean section, and (4) maternal/neonatal safety. Currently, calcium carbonate is used by clinicians in patients with varying characteristics, at varying doses, and at various times in their labor process based on their professional preference and experience. The investigators will implement a standardized treatment protocol for calcium carbonate use within a defined patient population who voluntarily agree to prospectively receive the intervention and then analyze predetermined safety and efficacy outcomes in comparison to a historical cohort of patients meeting the criteria for the defined patient population who did not have any documented calcium carbonate use during labor.

• Study Type: Interventional
• Enrollment (Actual): 250
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Wisconsin
    • Milwaukee, Wisconsin, United States, 53233
      • Aurora Sinai Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adult laboring patients ( ≥ 18 years of age)
• Able to speak and read English or Spanish (for historical cohort, preferred language should be English or Spanish)
• Singleton gestation
• Greater ≥ 37 weeks gestation in vertex presentation
• Present for induction of labor inclusive of medical indication, elective indication at greater than 39 weeks gestation, trial of labor after cesarean
• Receive standard-dose oxytocin during induction

Exclusion Criteria:

• Participants will be excluded from the study if they do not meet the above inclusion criteria or they will be further excluded under the following circumstances:
• Known need for cesarean section prior to induction of labor
• Known allergy to calcium carbonate
• Known contraindication to taking calcium carbonate including renal calculus, high urine calcium levels, elevated serum calcium, low serum phosphate, achlorhydria, or suspected digoxin toxicity.
• Inability to tolerate oral intake (i.e., nausea/vomiting)
• Need to be nothing by mouth (NPO)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Prospective Treatment Group; Patients receive calcium carbonate (500mg every 4 hours, per standardized treatment protocol) plus standard-dose oxytocin for labor induction	Dietary supplement: Calcium Carbonate; We will be using it in routes and doses consistent with its approved uses. Per the drug label information for Calcium Carbonate USP 500 mg found in the US National Library of Medicine, adults may take 2-4 tablets as symptoms occur and if pregnant to not exceed 10 tablets in 24 hours. Therefore, using a dosing of 500mg every 4 hours will be well below that guidance. When both cervical ripening has been completed and the oxytocin administration begins, the calcium carbonate treatment group will be given calcium carbonate 500mg every 4 hours (not to exceed 10 tablets in 24 hours) until they deliver.
No Intervention: Retrospective Historical Control Group; Patients who presented for induction at the same institution within the previous three years and received standard-dose oxytocin alone for labor induction and were not treated with calcium carbonate

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Duration of induction time	Participants in the treatment group will have a shorter duration of induction with oxytocin than those in the retrospective historical control group.	During the intervention (time from duration of induction with oxytocin start to delivery)
Rate of labor dystocia	Participants in the treatment group will have a lower rate of labor dystocia than those in the retrospective historical control group.	During the intervention (measured from time of induction to delivery)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of cesarean deliveries	Participants in the treatment group will have a lower rate of cesarean deliveries than those in the retrospective historical control group.	During the intervention (measured from time of induction to delivery)
Total amount of oxytocin after cervical ripening	Participants in the treatment group will receive a lower amount of oxytocin than those in the retrospective historical control group.	During the intervention (time on oxytocin after cervical ripening completed to delivery)
Gastrointestinal side effects	Participants in the treatment group will describe gastrointestinal side effects.	During the intervention (time on calcium carbonate to delivery)
Blood loss	Participants in the treatment group will experience less blood loss than those in the retrospective historical control group.	Time from delivery to 24 hours of birth
Rate of postpartum hemorrhage (>/= 500mL)	Participants in the treatment group will experience less postpartum hemorrhage than those in the retrospective historical control group.	Time from delivery to 24 hours of birth
Neonatal composite adverse outcomes	Neonates of participants in the treatment group will have comparable composite adverse outcomes to those born to participants in the retrospective historical control group.	Immediately after the birth until the time of discharge, an average of 3 days

Collaborators and Investigators

• Sponsor: Wake Forest University Health Sciences
• Investigators: Principal Investigator: Marie Forgie, DO, Wake Forest University Health Sciences

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2024
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): December 30, 2026

Study Registration Dates

• First Submitted: March 7, 2024
• First Submitted That Met QC Criteria: April 1, 2024
• First Posted (Actual): April 8, 2024

Study Record Updates

• Last Update Posted (Actual): November 21, 2025
• Last Update Submitted That Met QC Criteria: November 19, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Pregnancy; Uterine contraction; Calcium carbonate; Labor dystocia; Labor induction time
• Additional Relevant MeSH Terms: Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Obstetric Labor Complications; Pregnancy Complications; Dystocia; Inorganic Chemicals; Minerals; Calcium Compounds; Carbon Compounds, Inorganic; Carbonates; Carbonic Acid; Calcium Carbonate
• Other Study ID Numbers: IRB00107112

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Study data will only be shared with those listed on the study team as approved by the internal IRB.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No