Oxytocin Receptor Expression in Pregnancy

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Oxytocin Receptor Expression in Pregnancy: When Does it Turn on

Conditions
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Post-Abortion, Hemorrhage, Obstetric

Intervention / Treatment
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* Other: Myometrial tissue sample collection


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| 2nd trimester<br>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<br>* Myometrial tissue samples by core needle biopsy under ultrasound guidance<br>|
| Non-pregnant<br>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<br>* Myometrial tissue samples by core needle biopsy under ultrasound guidance<br>|
| 1st trimester<br>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<br>* Myometrial tissue samples by core needle biopsy under ultrasound guidance<br>|
| After term pregnancy (3rd trimester)<br>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<br>* Myometrial tissue samples by core needle biopsy under ultrasound guidance<br>|

What is the study measuring?
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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 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Post-abortion hemorrhage, Obstetric hemorrhage, Preterm labor, Abnormal labor, Oxytocin, Oxytocin receptor