An observational study in Labor Analgesia, Labor Pain and Oxytocin, sponsored by Ankara City Hospital Bilkent. Not yet recruiting at 1 site in Turkey (Türkiye). Open to female participants aged 18 Years to 40 Years. Per ClinicalTrials.gov, last updated 2026-10-19.
Sponsored by Ankara City Hospital Bilkent · Observational
Oxytocin is a key hormone that regulates uterine contractions during labor. Dural Puncture Epidural Analgesia (DPEA) is a modern technique for labor pain relief that provides faster onset and more reliable analgesia than standard epidural.While it is known that neuraxial analgesia can suppress oxytocin levels, it is unclear whether this effect depends on the stage of labor at which analgesia is administered. This prospective comparative study will enroll 120 pregnant women in spontaneous labor who request DPEA, divided into two groups: Early group (cervical dilation≤5 cm, n=60) and Late group (cervical dilation≥6 cm , n=60). Both groups receive identical DPEA (a total volume of 15 mL containing 0.1% bupivacaine and 100 µg fentanyl is administered through the epidural catheter, following dural puncture with a 26G spinal needle without intrathecal drug injection). The primary outcome is the percentage change in plasma oxytocin from baseline (T-0, before analgesia) to T-Eff (30 minutes after onset of effective analgesia defined as VAS\<2). Patients who received any exogenous oxytocin (induction or augmentation) before T-0 are excluded to ensure that the measured oxytocin represents endogenous production. The study will contribute to understanding how the timing of neuraxial analgesia relative to labor progression affects the endogenous oxytocin system, with potential implications for optimal clinical timing of labor analgesia administration.
Background:
Oxytocin is a neuropeptide produced in the hypothalamus and released from the posterior pituitary in a pulsatile manner during labor. Through the Ferguson reflex, oxytocin release increases substantially as labor progresses, with peak release around delivery. The effect of neuraxial analgesia on oxytocin dynamics has been controversial. Previous studies have reported both suppression and no significant change in oxytocin levels following epidural analgesia. DPEA, a technique that involves controlled dural puncture to enhance epidural local anesthetic spread without intrathecal drug administration, provides an opportunity to investigate whether the oxytocin response to neuraxial analgesia varies according to the stage of labor.
Design:
This is a prospective, comparative, observational cohort study. Patients are not randomized. Participants are classified into two groups according to cervical dilation at the time of DPEA request: Early Labor Group (≤5 cm) and Late Labor Group (≥6 cm). All participants receive standardized DPEA. Laboratory personnel performing oxytocin assays are blinded to group assignment.
DPEA protocol: After sterile preparation and local infiltration with 1% lidocaine, the epidural space is identified at L3-L4 or L4-L5 using a 17G Tuohy needle and loss-of-resistance technique. A 26G spinal needle is passed through the Tuohy needle to perform dural puncture, and cerebrospinal fluid return is confirmed. No intrathecal drug is administered. The spinal needle is withdrawn and the epidural catheter is advanced 5 cm into the epidural space. Following negative aspiration and an appropriate test dose, a total volume of 15 mL containing 0.1% bupivacaine and 100 µg fentanyl is administered through the epidural catheter. Maintenance analgesia is provided with patient-controlled epidural analgesia (PCEA).** Blood sampling: A baseline blood sample (T-0) is obtained immediately before DPEA. The time at which the patient first reports a VAS pain score \<2 is recorded as T-VAS; no blood sample is obtained at this time. The second blood sample (T-Eff) is obtained 30 minutes after T-VAS. Plasma samples are stored at -80°C until batch analysis for oxytocin concentration.** The primary outcome is the percentage change in maternal plasma oxytocin concentration from T-0 to T-Eff, calculated as: [(T-Eff - T-0) / T-0] × 100. Patients who receive exogenous oxytocin before the T-0 blood sample are excluded from the study.
409 studies on the registry are indexed under Labor Pain; 69 are open to participants now.
This study's planned enrollment of 120 is close to the median of 120 across 59 observational studies indexed under Labor Pain.
Browse Labor Pain studies →Ankara City Hospital Bilkent is the lead sponsor of 437 studies on the registry; 109 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Pregnant women aged 18-40 years admitted to the Labor Ward of Ankara Bilkent City Hospital with spontaneous labor who request Dural Puncture Epidural Analgesia (DPEA). Participants will be classified according to cervical dilation at the time of DPEA request as Early Labor Group (≤5 cm) or Late Labor Group (≥6 cm). Eligible participants will have a singleton, vertex pregnancy at 37-41 weeks of gestation and ASA physical status II.
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:
CRITICAL EXCLUSION (methodological requirement):
STANDARD EXCLUSION:
Pregnant women in spontaneous labor who request Dural Puncture Epidural Analgesia (DPEA) when cervical dilation is 5 cm or less. All receive standardized DPEA with a total volume of 15 mL containing 0.1% bupivacaine and 100 µg fentanyl via epidural catheter after dural puncture (26G) without intrathecal drug injection. Plasma oxytocin measured at T-0 (before DPEA) and T-Eff (30 min after VAS\<2).
Procedure: Dural Puncture Epidural Analgesia (DPEA)
Pregnant women in spontaneous labor who request Dural Puncture Epidural Analgesia (DPEA) when cervical dilation is 6 cm or greater. DPEA protocol identical to Early Group. Plasma oxytocin measured at same timepoints (T-0 and T-Eff).
Procedure: Dural Puncture Epidural Analgesia (DPEA)
Standard clinical DPEA procedure: Combined spinal-epidural kit used to locate epidural space at L3-L4 or L4-L5 with 17G Tuohy needle (loss of resistance). A 26G spinal needle is passed through the Tuohy needle to perform dural puncture; CSF return is confirmed. NO intrathecal drug is administered. The spinal needle is withdrawn, the epidural catheter is advanced 5 cm into the epidural space. After negative aspiration and test dose, 15 mL of 0.1% bupivacaine is administered through the epidural catheter. Maintenance analgesia is provided via patient-controlled epidural analgesia (PCEA).
Standard clinical DPEA procedure: Combined spinal-epidural kit used to locate epidural space at L3-L4 or L4-L5 with 17G Tuohy needle (loss of resistance). A 26G spinal needle is passed through the Tuohy needle to perform dural puncture; CSF return is confirmed. NO intrathecal drug is administered. The spinal needle is withdrawn, the epidural catheter is advanced 5 cm into the epidural space. After negative aspiration and test dose, 15 mL of 0.1% bupivacaine is administered through the epidural catheter. Maintenance analgesia is provided via patient-controlled epidural analgesia (PCEA).
Percentage change in maternal plasma oxytocin concentration from baseline to T-Eff
Calculated as: \[(T-Eff plasma oxytocin - T-0 plasma oxytocin) / T-0 plasma oxytocin\] × 100. Positive values indicate an increase in oxytocin; negative values indicate suppression. Plasma oxytocin concentration will be measured in pg/mL using an enzyme-linked immunosorbent assay (ELISA).
Time frame: From T-0 (immediately before DPEA) to T-Eff (30 minutes after onset of effective analgesia defined as VAS<2); total duration approximately 35-45 minutes depending on time to VAS<2. (VAS: Visual analogue scale 0-10 poits. 10 means worst pain)
Time to effective analgesia (VAS<2). (VAS: Visual analogue scale 0-10 poits. 10 means worst pain)
Duration in minutes from DPEA injection to the first time point when patient reports VAS pain score \<2. (VAS: Visual analogue scale 0-10 poits. 10 means worst pain)
Time frame: Within 30 minutes of DPEA administration
Cervical dilation progression rate
Rate of cervical dilation in cm/hour from DPEA administration to delivery.
Time frame: From DPEA to delivery (variable, typically 1-6 hours)
Bromage motor block score
Degree of motor block assessed by Bromage scale (0=no block, 3=complete block).
Time frame: At delivery
Need for post-T-Eff oxytocin augmentation
Binary outcome: whether exogenous oxytocin was initiated after T-Eff for labor augmentation (yes/no), start time, and initial dose
Time frame: From T-Eff to delivery
Mode of delivery
Vaginal, instrumental, or cesarean delivery; if cesarean, indication is recorded.
Time frame: At delivery
First and second stage durations
Duration of first stage (from DPEA to full dilation) and second stage (full dilation to delivery) in minutes.
Time frame: At delivery
Neonatal Apgar scores (0-10 points. 10 is the best score)
Apgar scores at 1 and 5 minutes of life.
Time frame: At 1 and 5 minutes after delivery
Umbilical cord blood pH
pH value from umbilical cord arterial blood.
Time frame: Immediately after delivery
Hemodynamic parameters
Systolic blood pressure (SBP) and heart rate (HR) at baseline, 5, 10, 15, 20, and 30 minutes after DPEA
Time frame: 0-30 minutes after DPEA
Plan to share: No — The investigators do not plan to share individual participant data (IPD) outside the research team. Aggregate results will be published in peer-reviewed journals and presented at scientific conferences. Any further data sharing requests may be considered on a case-by-case basis with appropriate institutional and ethical approval.
Start is estimated for Nov 2026; primary completion for May 2027, 6 months later.
Of 31 non-industry observational studies under Labor Pain, half reached primary completion within 9 months of starting (the median), counting those still running; a quarter within 6 and three quarters within 32. This study's planned 6 months is below that.
Counting every sponsor, half of 32 studies reached it within 9 months; a quarter within 6 and three quarters within 32.
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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