Oral Contraceptive (OC) Estrogen Dose and Breast Proliferation (OCP2)

February 12, 2026 updated by: University of Southern California

The Effects of Dose and Formulation of Oral Contraceptives (OCs) on Breast-Cell Proliferation: Can the Chemopreventive Effects of OCs on Endometrial and Ovarian Cancer be Extended to Breast Cancer?

The purpose of this research study is to gain a better understanding of the changes that may occur in the breast when a woman uses an oral contraceptive (birth control pill). Some research indicates that women who use birth control pills with lower amounts of estrogen (a hormone in the birth control pill) may have lower breast cell growth than women who use birth control pills with a higher amount of estrogen; this research will examine that in detail.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

82

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Los Angeles, California, United States, 90033
        • USC University Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 35 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Age 18-35
  2. BMI <30 kg/m2
  3. Premenopausal with regular cycles or currently taking an OC
  4. Not currently or recently pregnant or nursing (within previous 6 months)
  5. Non-smoker
  6. No use of antibiotics within the prior 4 weeks
  7. Competent to provide written informed consent (as judged by study team)
  8. Willing to adhere to the OC regimen
  9. Willingness to refrain from the use of aspirin or NSAIDS 10 days pior to the biopsy appointment and one week following the biopsy procedure
  10. Willing and able to refrain from use of fish oils 10 days prior to the biopsy appointment and one week following the biopsy procedure

Exclusion Criteria:

  1. Diabetes
  2. Abnormal breast examination
  3. Abnormal PT/INR and/or CBC with platelets test results (as determined by one of the study physicians)
  4. History or current therapeutic or prophylactic use of anticoagulants
  5. Known bleeding disorder or history of unexplained bleeding or bruising
  6. History of breast cancer or previous diagnostic breast biopsy
  7. Known allergy to local anesthetic

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Ortho-Novum® 1/35
Ortho-Novum® 1/35 is an oral contraceptive that contains more progestin.
Drug: Oral Contraceptive: Ortho-Novum® 1/35
Oral Contraceptive: Ortho-Novum® 1/35, pill, 2-3 mos, daily.
Active Comparator: Ovcon® 35
Ovcon® 35 is an oral contraceptive that contains less progestin.
Drug: Oral Contraceptive: Ovcon® 35
Oral Contraceptive: Ovcon® 35, pill, 2-3 mos, daily.
Active Comparator: Microgestin Fe® 1/20
is an oral contraceptive that contains less estrogen.
Drug: Oral Contraceptive: Microgestin Fe® 1/20
Oral Contraceptive: Microgestin Fe® 1/20, pill, 2-3 mos, daily.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Breast Cell Proliferation Levels Between the Three Oral Contraceptive Groups
Time Frame: Up to 3 months.
Percent of cells expressing staining for Ki67 will be examined in breast epithelial cells
Up to 3 months.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Southern California

Investigators

  • Principal Investigator: Heather MacDonald, M.D., University of Southern California

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 14, 2011

Primary Completion (Actual)

June 30, 2014

Study Completion (Actual)

June 30, 2015

Study Registration Dates

First Submitted

March 16, 2011

First Submitted That Met QC Criteria

March 17, 2011

First Posted (Estimated)

March 18, 2011

Study Record Updates

Last Update Posted (Actual)

February 17, 2026

Last Update Submitted That Met QC Criteria

February 12, 2026

Last Verified

January 1, 2018

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HS-10-00455

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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