Oxytocin Receptor Expression in Pregnancy

Oxytocin Receptor Expression in Pregnancy: When Does it Turn on

This study aims to determine when during gestation oxytocin receptor (OXTR) expression increases in the myometrium, which will contribute new insight to the management of obstetric hemorrhage and our understanding of normal and abnormal labor.

Study Overview

• Status: Active, not recruiting
• Conditions: Post-Abortion; Hemorrhage, Obstetric
• Intervention / Treatment: Other: Myometrial tissue sample collection

Detailed Description

In this descriptive study, we will obtain myometrial tissue samples by core needle biopsy under ultrasound guidance in anesthetized women immediately following surgical abortion and from controls, all of whom are undergoing a separate planned obstetric/gynecologic surgery. Tissue studies will be performed on these biopsy samples to examine oxytocin receptor expression and function.

• Study Type: Observational
• Enrollment (Estimated): 30

Contacts and Locations

Study Locations

• United States
  • Oregon
    • Portland, Oregon, United States, 97239
      • Oregon Health & Science University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

This is a study of reproductive age women over 18 years of age being performed at Oregon Health & Science University (OHSU) in Portland, OR. It will include subjects who present for pre-operative appointments in our outpatient Center for Women's Health Family Planning Clinic and OHSU Labor and Delivery.

Description

Inclusion Criteria:

• Women age 18-50
• Gestational age 14-26 weeks; or 6-13 weeks, 37-42 weeks, or non-pregnant (controls)
• Undergoing another planned surgical procedure with anesthesia (suction D&C, D&E, gravid hysterectomy, cesarean section, or laparoscopic tubal ligation)
• Able to give informed consent in English or Spanish

Exclusion Criteria:

To optimize biopsy safety, we will exclude patients with anticipated difficult cases, that have additional risks of hemorrhage, or those with features that limit ultrasound visualization.

Increased risk of hemorrhage:

• Anemia (Hgb < 9)
• Anticoagulation, bleeding disorder, or coagulopathy
• Multiple gestation
• Infection or sepsis

For ultrasound-guided procedures:

• Obese, BMI ≥ 40
• History of ≥2 cesarean sections
• Large fibroids or uterine anomalies obstructing view
• Other poor visualization
• Thin myometrium < 1cm

Study Plan

How is the study designed?

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
2nd trimester; Second trimester myometrial tissue samples will be collected by core needle biopsy under ultrasound guidance in anesthetized women. Samples will be obtained primarily after second trimester surgical abortions or Dilation and Evacuation (D&E) procedures as well as after rare gravid hysterectomies or after late second trimester cesarean deliveries.	Other: Myometrial tissue sample collection; Myometrial tissue samples by core needle biopsy under ultrasound guidance
Non-pregnant; Myometrial tissue samples will be collected by core needle biopsy under ultrasound guidance in non-pregnant women undergoing gynecologic surgery under anesthesia for laparoscopic tubal ligation.	Other: Myometrial tissue sample collection; Myometrial tissue samples by core needle biopsy under ultrasound guidance
1st trimester; First trimester myometrial tissue samples will be collected by core needle biopsy under ultrasound guidance in anesthetized women. Samples will be obtained after first trimester surgical abortions or suction dilation and curettage (D&C).	Other: Myometrial tissue sample collection; Myometrial tissue samples by core needle biopsy under ultrasound guidance
After term pregnancy (3rd trimester); Third trimester myometrial tissue samples will be collected by core needle biopsy under ultrasound guidance in anesthetized women. Samples will be obtained at the time of cesarean delivery.	Other: Myometrial tissue sample collection; Myometrial tissue samples by core needle biopsy under ultrasound guidance

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Oxytocin receptor expression	Measure of oxytocin receptor expression. Perform quantitative RT-PCR on mRNA extracted from biopsy samples obtained from subjects at the end of their procedure (within 30 minutes).	30 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Function of myometrial oxytocin receptor	Assessment of the function of the myometrial oxytocin receptor. Measure intracellular calcium in cultured myometrial cells after activating the receptor with oxytocin from biopsy samples obtained from subjects at the end of their procedure (within 30 minutes).	30 minutes

Collaborators and Investigators

• Sponsor: Oregon Health and Science University
• Investigators: Principal Investigator: Jessica Reid, MD, Oregon Health and Science University

Study record dates

Study Major Dates

• Study Start (Actual): June 3, 2019
• Primary Completion (Actual): August 22, 2020
• Study Completion (Estimated): August 1, 2025

Study Registration Dates

• First Submitted: April 5, 2019
• First Submitted That Met QC Criteria: April 8, 2019
• First Posted (Actual): April 9, 2019

Study Record Updates

• Last Update Posted (Actual): May 31, 2025
• Last Update Submitted That Met QC Criteria: May 27, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: Oxytocin; Preterm labor; Obstetric hemorrhage; Oxytocin receptor; Post-abortion hemorrhage; Abnormal labor
• Additional Relevant MeSH Terms: Pathologic Processes; Hemorrhage
• Other Study ID Numbers: OHSU IRB 19417

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
• product manufactured in and exported from the U.S.: No