Pharmacokinetic and Pharmacodynamic Investigations of Fetal Anesthesia During Maternal Fetal Surgery

This study examines how three medications commonly used during fetal surgery, fentanyl, rocuronium, and atropine, behave in the fetus. The primary goal is to understand their pharmacokinetics (how the drugs are absorbed, distributed, and cleared), pharmacodynamics (how they affect fetal physiology), and how they transfer between mother and fetus through the placenta. The secondary goal is to measure drug levels in discarded fetal blood samples collected during clinically indicated procedures and relate those levels to fetal heart rate, heart rate variability, movement, gestational age, and fetal size. An optional maternal blood draw component will allow comparison of maternal and fetal drug concentrations to better understand placental transfer. The study does not change clinical care or require extra fetal procedures, and findings may help create safer, evidence-based fetal anesthesia dosing strategies tailored to gestational age.

Study Overview

• Status: Not yet recruiting
• Conditions: Fetal Anesthesia

• Study Type: Observational
• Enrollment (Estimated): 10

Contacts and Locations

• Study Contact: Name: Rachel Bernier, BS, MPH; Phone Number: 857-218-5348; Email: rachel.bernier@childrens.harvard.edu
• Study Contact Backup: Name: Julia Atayde, BS; Phone Number: 617-355-2967; Email: julia.atayde@childrens.harvard.edu

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Boston Children's Hospital
      • Contact: Gwen Owens, MD, PhD; Phone Number: 515-720-3908; Email: gwen.owens@childrens.harvard.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Pregnant women undergoing maternal-fetal surgery

Description

Inclusion Criteria:

• Pregnant and undergoing maternal-fetal surgery requiring clinically indicated fetal anesthesia and planned fetal blood sampling as part of usual fetal care
• Fetus is with or without congenital heart disease

Exclusion Criteria:

• Patient or fetus have any known liver or kidney disease
• Patient or fetus has any known allergy to fentanyl, rocuronium, or atropine
• Patient has taken inhibitors, inducers or substrates of CYP3A4 other than midazolam (including erythromycin, ranitidine, verapamil, antihistamines, and dextromethorphan) within 24 hours of surgery.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Pregnant women undergoing maternal-fetal surgery; Pregnant women undergoing maternal-fetal surgery requiring fetal anesthesia. This study is purely observational.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum plasma concentration (Cmax) of fetal anesthesia	Characterize the plasma concentrations / pharmacokinetics profile, specifically the peak plasma concentration (Cmax) of commonly used fetal anesthetics, investigate the pharmacodynamic effects of anesthetics on fetus, assess the maternal-fetal transfer of anesthetics during surgery, and identify potential variations during different stages of fetal development.	2 years
Area under the plasma concentration versus time curve (AUC) of fetal anesthesia	Characterize the plasma concentrations / pharmacokinetics profile, specifically the area under the plasma concentration versus time curve (AUC) of commonly used fetal anesthetics, investigate the pharmacodynamic effects of anesthetics on fetus, assess the maternal-fetal transfer of anesthetics during surgery, and identify potential variations during different stages of fetal development.	2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maternal blood concentration of fetal anesthesia	Measure the maternal blood concentration of fetal anesthesia to characterize fetal-maternal transfer of commonly used fetal anesthetics.	2 years
Fetal blood concentration of maternal anesthesia	Measure the fetal blood concentration of maternal anesthesia to characterize fetal-maternal transfer of commonly used maternal anesthetics.	2 years

Collaborators and Investigators

• Sponsor: Boston Children's Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): May 1, 2026
• Study Completion (Estimated): May 1, 2027

Study Registration Dates

• First Submitted: April 20, 2026
• First Submitted That Met QC Criteria: April 30, 2026
• First Posted (Actual): May 6, 2026

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: April 30, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: fetal; intrauterine; intrauterine transfusion; fetal anesthesia; fetal cardiac intervention; iut
• Other Study ID Numbers: IRB-P00051770

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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