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Oral Calcium Supplementation in Labor

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Arrowhead Regional Medical Center

Status and phase

Completed
Phase 3
Phase 2

Conditions

Labor Dystocia
Uterine Contraction
Labor Active Dilated Cm
Labor Duration
Labor
Labor Delivery
Labor Complication

Treatments

Drug: Calcium carbonate

Study type

Interventional

Funder types

Other

Identifiers

Details and patient eligibility

About

The goal of this clinical trial is to learn if oral calcium carbonate can improve uterine contractions and labor outcomes in term pregnancies. It will also evaluate the safety of calcium carbonate when used during labor. The main questions it aims to answer are:

Does oral calcium carbonate increase uterine contraction strength? Does it lead to shorter labor duration or higher vaginal delivery rates? What side effects or complications, if any, occur with calcium carbonate use during labor?

Researchers will compare oral calcium carbonate to no treatment to see if it helps improve labor efficiency and reduce cesarean delivery rates.

Participants will:

Be randomly assigned to receive either 2,000 mg of oral calcium carbonate or no intervention Undergo monitoring with an intrauterine pressure catheter to measure contraction strength Be observed for two hours without oxytocin to assess calcium's direct effect on contractions Have data collected on labor progression, delivery outcomes, and neonatal health

Full description

In the United States, nearly one-third of deliveries are performed via cesarean section, with labor dystocia remaining a leading indication. Labor dystocia may result from a variety of maternal and fetal factors, including malposition, cephalopelvic disproportion, or ineffective uterine contractions. When contractions are inadequate, the standard intervention is intravenous oxytocin. However, prolonged or high-dose oxytocin administration can lead to receptor desensitization, reducing its effectiveness and increasing the risk of postpartum hemorrhage.

Calcium plays a key role in myometrial contractility by facilitating calcium influx through L-type channels in myometrial cells, which triggers intracellular calcium release and action potentials. During labor, upregulation of calcium channels enhances the uterus's responsiveness to contractile stimuli. Elevated serum calcium levels have been associated with stronger and more effective contractions.

Adjunctive intravenous calcium administration with oxytocin has been shown to improve labor outcomes, including higher rates of vaginal delivery within 24 hours of induction and reduce blood loss in cesarean deliveries. However, the potential role of oral calcium supplementation in enhancing labor progression has not been evaluated in clinical trials. Given its physiological relevance, accessibility, and low-risk profile, oral calcium may represent a simple adjunct to improve labor efficiency and reduce cesarean rates.

This study aims to evaluate the impact of oral calcium carbonate supplementation during labor on uterine contractility and clinical outcomes. The investigators hypothesize that calcium carbonate administered intrapartum will enhance uterine contractions, resulting in higher vaginal delivery rates, shorter time to delivery, and reduced blood loss.

Enrollment

89 patients

Sex

Female

Ages

18+ years old

Volunteers

No Healthy Volunteers

Inclusion criteria

  • Had an intrauterine pressure catheter in place
  • Term gestation, greater than or equal to 37 weeks of gestation
  • Singleton pregnancy
  • Cephalic presentation
  • > 18 years of age

Exclusion criteria

  • incarceration
  • multiple gestation
  • active illicit drug use
  • abnormal clinical pelvimetry
  • Suspected fetal macrosomia defined as estimated fetal weight ≥4250 grams
  • intrauterine growth restriction
  • abnormal placentation
  • prior cesarean delivery
  • maternal history of arrhythmia
  • hyperparathyroidism
  • heart failure
  • renal or hepatic failure
  • nephrolithiasis
  • receipt of medications known to affect uterine contractility-such as magnesium sulfate, terbutaline, or recent misoprostol in the last four hours

Trial design

Primary purpose

Treatment

Allocation

Randomized

Interventional model

Parallel Assignment

Masking

None (Open label)

89 participants in 2 patient groups

Standard of care
No Intervention group
Description:
Received no medications but monitored for the duration of the study
Calcium carbonate
Experimental group
Description:
2,000 mg PO calcium carbonate as a single dose
Treatment:
Drug: Calcium carbonate

Trial documents
1

Trial contacts and locations

1

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Data sourced from clinicaltrials.gov

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