A Phase 4 interventional study of Tramadol Hydrochloride and Paracetamol (acetaminophen) in Labor Pain, sponsored by Universidad Nacional Autonoma de Honduras. Recruiting at 2 sites in Honduras. Open to female participants aged 15 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-05.
Sponsored by Universidad Nacional Autonoma de Honduras · Phase 4, Interventional, and Treatment
This randomized, double-blind, placebo-controlled trial aims to compare the analgesic efficacy and obstetric effects of tramadol (100 mg IV) versus paracetamol (1 g IV) versus placebo (saline solution) in nulliparous women during active labor. The primary outcome is duration of active labor (minutes). Secondary outcomes include duration of expulsive phase, type of delivery, need for oxytocin augmentation, maternal adverse events (nausea, vomiting, somnolence, hypotension), and neonatal outcomes (Apgar scores at 1 and 5 minutes, NICU admission). The study hypothesizes that tramadol significantly reduces active labor duration compared to paracetamol and placebo, without compromising maternal or neonatal safety. A total of 300 nulliparous women (100 per group) will be enrolled at Hospital Escuela, Tegucigalpa, Honduras.
This is a randomized, double-blind, parallel-group, superiority efficacy trial comparing three interventions: tramadol 100 mg IV, paracetamol 1 g IV, and placebo (10 mL 0.9% saline solution) administered at the onset of active labor (cervical dilation ≥4 cm with regular contractions). The study design follows CONSORT guidelines for randomized controlled trials. Randomization will be performed using REDCap's automated randomization module in variable block sizes, ensuring allocation concealment. Double-blinding is maintained: participants, care providers, and outcome assessors are masked to group assignment. The primary endpoint is duration of active labor (minutes from intervention administration to complete cervical dilation). Secondary endpoints include: duration of expulsive phase (minutes), type of delivery (spontaneous vaginal, instrumental, cesarean), need for oxytocin augmentation, maternal adverse events (nausea, vomiting, somnolence, hypotension, pruritus, dizziness), neonatal Apgar scores at 1 and 5 minutes, birth weight, meconium-stained amniotic fluid, NICU admission, and neonatal asphyxia. Data collection includes sociodemographic variables (age, education, marital status, occupation), obstetric variables (gestational age, prenatal care visits, BMI, membrane status, cervical dilation at intervention, baseline fetal heart rate), and pain scores (Visual Analog Scale pre-intervention, 30 min, 1h, 2h post-intervention). Statistical analysis includes ANOVA or Kruskal-Wallis for continuous variables, chi-square for categorical variables, and logistic regression for binary outcomes, with significance set at p\<0.05. A Data Safety Monitoring Board will oversee safety every 3 months. The study is funded by Universidad Nacional Autónoma de Honduras and will be conducted at Hospital Escuela, Tegucigalpa, from Feb. 2026 to June 2026.
423 studies on the registry are indexed under Labor Pain; 74 are open to participants now.
This study's planned enrollment of 300 is above the median of 100 across 347 interventional studies indexed under Labor Pain.
Browse Labor Pain studies →Universidad Nacional Autonoma de Honduras is the lead sponsor of 13 studies on the registry; 8 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
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.
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.
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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.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
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Participants receive a single dose of tramadol 100 mg intravenously at the onset of active labor (cervical dilation ≥4 cm with regular contractions).
Drug: Tramadol Hydrochloride
Participants receive a single dose of paracetamol 1 g intravenously (slow infusion) at the onset of active labor (cervical dilation ≥4 cm with regular contractions).
Drug: Paracetamol (acetaminophen)
Participants receive a single dose of 10 mL 0.9% saline solution intravenously at the onset of active labor (cervical dilation ≥4 cm with regular contractions).
Drug: Placebo (Saline Solution)
Tramadol 100 mg administered as a single intravenous dose at the onset of active labor. Tramadol is an atypical opioid analgesic with serotonin and noradrenaline reuptake inhibition properties. The dose is within standard clinical ranges for obstetric analgesia. Administration is performed by trained medical personnel following institutional protocols. Participants are monitored for adverse effects including nausea, vomiting, somnolence, dizziness, and hypotension.
Paracetamol 1 g administered as a single intravenous slow infusion at the onset of active labor. Paracetamol is a central analgesic acting through COX-3 inhibition in the central nervous system. It is widely used during pregnancy and labor due to its favorable safety profile. Administration is performed by trained medical personnel following institutional protocols. Participants are monitored for adverse effects including nausea, vomiting, and allergic reactions (rare).
Placebo consisting of 10 mL 0.9% saline solution administered as a single intravenous dose at the onset of active labor. The appearance and administration procedure are identical to the active interventions to maintain blinding. No pharmacological active ingredients are present. Administration is performed by trained medical personnel following institutional protocols.
Duration of Active Labor
Time in minutes from administration of study intervention (at onset of active labor defined as cervical dilation ≥4 cm with regular contractions) to complete cervical dilation (10 cm) or delivery, whichever occurs first. Measured and recorded by attending obstetric staff using standardized timing protocols.
Time frame: From intervention administration (at active labor onset) up to 12 hours.
Duration of Expulsive Phase (Second Stage)
Time in minutes from complete cervical dilation (10 cm) to fetal expulsion. Measured and recorded by attending obstetric staff.
Time frame: During delivery, from complete cervical dilation up to 120 minutes.
Type of Delivery
Classification of delivery outcome: spontaneous vaginal delivery, instrumental delivery (forceps or vacuum), or cesarean section. Assessed by attending obstetrician.
Time frame: At delivery
Need for Oxytocin Augmentation
Requirement for additional oxytocin administration to augment uterine contractions during labor. Recorded as yes/no, including dose and timing if applicable.
Time frame: During labor (from intervention administration up to 24 hours).
Maternal Adverse Events
Occurrence of any adverse events potentially related to the intervention, including: nausea, vomiting, somnolence, dizziness, headache, pruritus, hypotension (systolic BP \<90 mmHg), or allergic reactions. Severity graded as mild, moderate, or severe.
Time frame: From intervention administration up to 24 hours postpartum.
Neonatal Apgar Score at 5 Minutes
Apgar score assessed at 5 minutes after birth. Score ranges from 0-10, with higher scores indicating better neonatal condition.
Time frame: At 5 minutes after birth.
Neonatal Complications
Occurrence of neonatal complications including: Apgar score \<7 at 5 minutes, meconium-stained amniotic fluid, need for neonatal resuscitation, NICU admission, or neonatal asphyxia
Time frame: From birth up to 48 hours, through hospital discharge.
Pain Scores (Visual Analog Scale)
Maternal pain assessed using Visual Analog Scale (VAS) from 0 (no pain) to 10 (worst imaginable pain). Measured at baseline (pre-intervention), 30 minutes, 1 hour, and 2 hours post-intervention.
Time frame: Pre-intervention, and at 30 minutes, 1 hour, and 2 hours post-intervention.
Subgroup Analysis by Maternal Age
Comparison of primary and secondary outcomes stratified by maternal age categories (\<20 years, 20-35 years, \>35 years).
Time frame: Throughout study period, average of six months
Plan to share: Undecided — Individual participant data (anonymized) will be shared for scientific purposes related to obstetric analgesia and labor management. Only de-identified datasets will be shared with qualified researchers upon reasonable request and with appropriate ethics committee approval. Participants will be informed of data sharing plans during the informed consent process and may opt out.
Started Feb 2026 (actual). Primary completion is estimated for Nov 2026, 9 months after the start.
Of 20 phase 4 interventional studies under Labor Pain, half reached primary completion within 28 months of starting (the median), counting those still running; a quarter within 11. This study's planned 9 months is below that.
Since we started tracking on Sep 25, 2026, the dates moved once, on Nov 5, 2026: primary completion Aug 2026 → Nov 2026 and completion Sep 2026 → Nov 2026.
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 ↗
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Studies of the drugs tested here: Tramadol · Acetaminophen
Universidad Nacional Autonoma de Honduras