An Ambispective, Observational Study to Evaluate the Cases of Neonatal Acute Hypoxia at Delivery Using Fetal Physiology-Based Interpretation and Eucapnic pH Assessment (NOAH)

Neonatal Outcomes After Acute Hypoxia: Re-evaluating Cardiotocography Traces Using Fetal Physiology-Based Interpretation and Eucapnic pH Assessment

This study aims to improve understanding of how fetuses respond to oxygen deprivation during labor by re-evaluating cardiotocography (CTG) recordings using a physiology-based interpretation approach and comparing these findings with umbilical cord blood gas measurements at birth, including eucapnic pH assessment.

The study will include term pregnancies and combines retrospective data analysis with prospective enrollment. Researchers will investigate whether physiology-based CTG interpretation can better identify signs of fetal compromise and whether eucapnic pH may improve the distinction between respiratory and metabolic acidosis. Findings may contribute to improving fetal monitoring strategies and the assessment of newborn condition at birth.

Study Overview

• Status: Not yet recruiting
• Conditions: Neonatal Acidemia and Hypoxia

Detailed Description

Cardiotocography (CTG) is widely used for intrapartum fetal surveillance; however, traditional pattern-recognition approaches may not always reflect the underlying fetal physiological response to hypoxic stress. Recently, physiology-based CTG interpretation frameworks have been proposed to improve identification of fetal compensation and decompensation mechanisms during labor.

Similarly, conventional interpretation of umbilical cord blood gas analysis may not adequately distinguish respiratory from metabolic components of neonatal acidemia. Eucapnic pH, calculated by correcting for the respiratory component of acid-base imbalance, has been proposed as a tool to better characterize metabolic compromise at birth.

This ambispective observational study aims to re-evaluate CTG tracings obtained during labor using a physiology-based interpretative framework and to integrate these findings with arterial umbilical cord blood gas parameters, including measured pH, base excess, pCO2, and calculated eucapnic pH.

The study includes a retrospective cohort of term singleton deliveries and a prospective cohort of consecutively enrolled term pregnancies undergoing intrapartum CTG monitoring. CTG recordings will undergo blinded re-evaluation by independent reviewers using physiology-based criteria. These findings will be integrated with maternal, intrapartum, and neonatal variables to explore relationships between CTG characteristics, types of hypoxic exposure, acid-base status, and neonatal outcomes.

The study aims to determine whether physiology-based CTG interpretation identifies fetal compromise not recognized using conventional interpretation methods and to evaluate the relationship between CTG findings, eucapnic pH, and neonatal condition at birth. The results may contribute to improving understanding of intrapartum fetal adaptation and refining strategies for fetal surveillance during labor.

• Study Type: Observational
• Enrollment (Estimated): 1000

Contacts and Locations

• Study Contact: Name: Silvio Tartaglia, MD, PhD; Phone Number: +390630157024; Email: silvio.tartaglia@policlinicogemelli.it
• Study Contact Backup: Name: Alessandro Petrecca, MD; Phone Number: +390630157024; Email: alessandro.petrecca@guest.policlinicogemelli.it

Study Locations

• Italy
  • Lazio
    • Rome, Lazio, Italy, 00168
      • UOC di Ostetricia e Patologia Ostetrica
      • Contact: Concetta Cesare; Phone Number: +390630158531; Email: att@policlinicogemelli.it
      • Sub-Investigator: Silvio Tartaglia, MD, PhD
      • Sub-Investigator: Alessandro Petrecca, MD
      • Sub-Investigator: Beatrice Valentini, MD
      • Sub-Investigator: Roberta Rullo, MD
      • Sub-Investigator: Alice Dal Miglio, MD
      • Sub-Investigator: Federico Quintiliani, MD
      • Sub-Investigator: Marta Vicidomini, MD
      • Sub-Investigator: Tullio Ghi, MD, PhD

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

The study population consists of women with term singleton pregnancies undergoing labor and delivery at a tertiary referral center. The study includes both retrospectively identified deliveries and prospectively enrolled pregnancies with available intrapartum cardiotocography (CTG) recordings and umbilical cord arterial blood gas analysis.

Description

Inclusion Criteria:

• Singleton pregnancies
• Term neonates (gestational age =or> 37 weeks)

• Availability of clinical data, such as

  • CTG tracing within 90 minutes before delivery
  • Umbilical cord blood gas analysis (arterial sample)
• Signed informed consent (only for the prospective arm)

Exclusion Criteria:

• Major fetal anomalies
• Incomplete or missing CTG or blood gas data
• Elective cesarean sections without labor

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Pregnant women who deliver neonates presenting hypoxia; Participants will include term singleton pregnancies undergoing labor and delivery with available intrapartum cardiotocography (CTG) recordings and umbilical cord arterial blood gas analysis. Two cohorts will be included: a retrospective cohort of eligible deliveries occurring between 2018 and 2025 and a prospective cohort of consecutively enrolled term pregnancies from 2026 onward. This is an observational study with no experimental intervention, treatment allocation, or modification of standard clinical care. The study involves collection of clinical data and re-evaluation of CTG tracings using a physiology-based interpretation framework combined with assessment of cord blood gas parameters, including eucapnic pH.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Detection of fetal decompensation using physiology-based CTG interpretation	proportion of cases in which physiology-based CTG interpretation identified features of fetal decompensation not evident in conventional interpretation	From labor admission until delivery (assessment performed using CTG recordings obtained within 90 minutes before delivery)

Collaborators and Investigators

• Sponsor: Fondazione Policlinico Universitario Agostino Gemelli IRCCS
• Investigators: Study Director: Tullio Ghi, Chief, Fondazione Policlinico Universitario Agostino Gemelli IRCCS

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: June 1, 2026
• First Submitted That Met QC Criteria: June 1, 2026
• First Posted (Actual): June 5, 2026

Study Record Updates

• Last Update Posted (Actual): June 5, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: cardiotocography; labor and delivery; eucapnic pH; neonatal hypoxia
• Additional Relevant MeSH Terms: Infant, Newborn, Diseases; Signs and Symptoms, Respiratory; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hypoxia; Asphyxia Neonatorum
• Other Study ID Numbers: 27264

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be shared because the study involves retrospective and prospective collection of sensitive clinical and perinatal data, and data sharing may not be compatible with institutional policies, participant privacy protection, and applicable data protection regulations.

Drug and device information, study documents

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