An interventional study of Transperineal Ultrasound and Vaginal Examination in Labor Active Dilated Cm, sponsored by Hospital Universitario La Paz. Recruiting at 1 site in Spain. Open to female participants aged 18 Years to 45 Years. Per ClinicalTrials.gov, last updated 2025-12-12.
Sponsored by Hospital Universitario La Paz · Not applicable, Interventional, and Diagnostic
This clinical trial aims to determine whether transperineal ultrasound (a perineal external scan) can improve decision-making for hospital admission in term pregnant women in labor compared to traditional vaginal examination. Term pregnant women (>37 weeks) presenting with contractions at the emergency department will be randomly assigned to undergo either a transperineal ultrasound or a vaginal examination upon arrival. The study will evaluate whether ultrasound-based assessment reduces the rate of labor inductions and decreases patient discomfort during the admission evaluation. All participants will receive standard clinical evaluation and follow-up according to the assigned method, report discomfort levels using a standardized scale, and have labor outcomes recorded - including induction, oxytocin use, time to delivery, and mode of delivery -, to determine whether ultrasound improves clinical decision-making and maternal comfort.
This single-center, prospective, randomized controlled clinical trial is designed to evaluate whether transperineal ultrasound provides a more effective and less discomforting method than standard vaginal examination for decision-making regarding hospital admission in term pregnant women presenting with contractions. Vaginal examination remains the standard approach for assessing labor progression but is known to be subjective, poorly reproducible, and frequently uncomfortable for patients. In contrast, transperineal ultrasound offers objective and reproducible parameters such as cervical dilation, fetal head station, angle of progression, and head-perineum distance. Incorporating these measurements into the clinical evaluation may optimize admission criteria, reduce unnecessary hospitalizations, and lower the rate of labor inductions. After obtaining informed consent, eligible participants will be randomly assigned in a 1:1 ratio to either a transperineal ultrasound group or a standard vaginal examination group. In the ultrasound group, hospital admission will be recommended when cervical dilation is ≥3 cm or the angle of progression exceeds 120°, in the presence of regular uterine contractions. In the vaginal examination group, admission will be recommended when cervical dilation is ≥4 cm with regular contractions. Maternal discomfort during the evaluation will be assessed on a 0-10 numerical scale, and all labor outcomes and interventions will be recorded in standardized case report forms. A total of 170 participants (85 per group) will be enrolled to detect an 18% difference in labor induction rates with 80% power and a 95% confidence level. Statistical analyses will include descriptive and comparative methods (Chi-square, t-test, or non-parametric equivalents), with significance defined as p\<0.05. The study will adhere to the principles of the Declaration of Helsinki and comply with applicable data protection regulations, including the Spanish Ley Orgánica de Protección de Datos (Organic Law on Data Protection, LOPD) and the European General Data Protection Regulation (GDPR).All participants will provide written informed consent prior to inclusion, and all data will be anonymized. The protocol has received approval from the institutional ethics committee. This trial builds upon prior observational findings demonstrating high agreement between ultrasound-based and traditional methods for assessing labor progression. By generating high-level evidence, it aims to support the implementation of transperineal ultrasound in labor triage protocols, improving the accuracy of clinical decision-making, enhancing maternal comfort, and contributing to better obstetric outcomes.
Exclusion Criteria:
Participants in this arm will undergo transperineal ultrasound to assess cervical dilatation, angle of progression (AOP), fetal head position, and head-perineum distance (HPD). Hospital admission will be based on predefined sonographic criteria (e.g., dilation ≥3 cm or angle of progression \>120° plus regular uterine contractions).
Diagnostic Test: Transperineal Ultrasound
Participants in this arm will undergo standard digital vaginal examination. Hospital admission will be based on cervical dilation ≥4 cm and regular uterine contractions, following the routine clinical protocol.
Diagnostic Test: Vaginal Examination
Transperineal ultrasound will be performed to assess cervical dilatation, angle of progression, fetal head position, and head-perineum distance. Admission decisions will be made based on predefined sonographic thresholds.
Standard digital vaginal examination will be conducted to assess cervical dilatation. Admission decisions will follow institutional protocol (≥4 cm dilation with regular contractions).
Rate of Labor Induction
Proportion of participants who undergo labor induction if admitted after evaluation by transperineal ultrasound or vaginal examination.
Time frame: From hospital admission decision to delivery
Use of Oxytocin for Labor Augmentation
Proportion of participants who receive oxytocin for augmentation of labor following initial triage evaluation.
Time frame: During labor (up to delivery)
Time from Admission to Delivery
Time frame: From hospital admission to time of delivery
Mode of Delivery (as recorded in the medical record)
Mode of delivery will be recorded from the medical record and categorized as spontaneous vaginal delivery, assisted vaginal delivery (instrumental), or cesarean section.
Time frame: At birth
Number of Vaginal Examinations Performed
Time frame: From hospital admission for labor to delivery
Plan to share: Yes — Individual participant data (IPD) that underlie the results reported in this study (after de-identification) will be made available to researchers upon reasonable request. This will include data on primary and secondary outcomes. Data will be shared after publication of the main results and with approval from the principal investigator and institutional ethics committee. Requests should be directed to Dr. Marcos J. Cuerva at marcosj.cuerva@salud.madrid.org
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Hospital Universitario La Paz