The Influence of Plan B® on Cardiovascular Health.

NCT07759635 | Recruiting

• 1 other identifier: LEVOH
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this double-blind randomized controlled trial is to learn about the impacts of a single dose of Plan B® on the cardiovascular system in young, health, premenopausal females. The main questions it aims to answer are:

1. 1.What is the short-term affect of Plan B® affect on the venous system?
2. 2.What is the short-term affect of Plan B® affect on the health of arteries?
3. 3.Undergo baseline measurements of venous thrombosis markers, blood pressure, and measures of arterial function using ultrasound.
4. 4.Be randomized to either take a Plan B® or placebo pill
5. 5.Repeat baseline measurements of venous thrombosis markers, blood pressure, and measures of arterial function using ultrasound each hour, for 6-hours, and then 24- and 48- hours after taking the Plan B® or placebo pill.

Conditions

Female; Premenopausal

Keywords

Emergency contraceptives; Hormonal contraceptives; Venous thrombosis; Endothelial function

Outcome Measures

Primary Outcomes (4)

• D-Dimer

  Measured in ug/L FEU from platelet poor plasma using the HemosIL® D-Dimer HS 500 assay, a latex immunoturbidimetric assay (LIA) on the ACL TOP analyzer.

  Baseline, 1-hour, 2-hours, 3-hours, 4-hours, 5-hours, 6-hours, 24-hours and 48-hours post-ingestion of Plan B/placebo

• Prothrombin fragment 1+2

  Measured in pg/mL from platelet-poor plasma using an enzyme-linked immunosorbent assay (ELISA).

  Baseline, 1-hour, 2-hours, 6-hours, 24-hours, and 48-hours post-ingestion of Plan B/placebo.

• Thrombin antithrombin

  Measured in pg/mL from platelet-poor plasma using an enzyme-linked immunosorbent assay (ELISA).

  Baseline, 1-hour, 2-hours, 6-hours, 24-hours, and 48-hours post-ingestion of Plan B/placebo.

• P-Selectin

  Measured in pg/mL from platelet-poor plasma using an enzyme-linked immunosorbent assay (ELISA).

  Baseline, 1-hour, 2-hours, 6-hours, 24-hours, and 48-hours post-ingestion of Plan B/placebo.

Secondary Outcomes (9)

• Brachial artery flow-mediated dilation

  Baseline, 1-hour, 2-hours, 3-hours, 4-hours, 5-hours, 6-hours, 24-hours and 48-hours post-ingestion of Plan B/placebo

• Levonorgestrel

  1-hour, 2-hours, 3-hours, 4-hours, 5-hours, 6-hours, 24-hours and 48-hours post-ingestion of Plan B/placebo

• Systolic blood pressure

  Baseline, 1-hour, 2-hours, 3-hours, 4-hours, 5-hours, 6-hours, 24-hours and 48-hours post-ingestion of Plan B/placebo

• Diastolic blood pressure

  Baseline, 1-hour, 2-hours, 3-hours, 4-hours, 5-hours, 6-hours, 24-hours and 48-hours post-ingestion of Plan B/placebo

• Mean arterial pressure

  Baseline, 1-hour, 2-hours, 3-hours, 4-hours, 5-hours, 6-hours, 24-hours and 48-hours post-ingestion of Plan B/placebo

Study Arms (2)

Plan B®

EXPERIMENTAL

1.5 mg Levonorgestrel

Drug: Plan B (Levonorgestrel)

Placebo

PLACEBO COMPARATOR

Gelatin capsule

Other: Placebo (gelatin capsule)

Interventions

Plan B (Levonorgestrel) DRUG

1 x dose of 1.5 mg levonorgestrel tablet over encapsulated to mimic placebo.

Plan B®

Placebo (gelatin capsule) OTHER

Gelatin capsule over encapsulated to mimic Plan B

Placebo

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Provide written informed consent.
• Pre-menopausal female.
• years of age.
• Naturally cycling (i.e., not using any form of hormonal contraception for ≥ 3 months).
• Eumenorrheic (i.e., experiencing a predictable menstrual cycle lasting 21-45 days).
• In the surrounding Hamilton area, or able to visit McMaster for study visits.
• Not pregnant.

You may not qualify if:

• Known hypersensitivity to the active substance levonorgestrel or to any ingredient in this formulation (i.e., levonorgestrel colloidal silicon dioxide, potato starch, magnesium stearate, talc, cornstarch, lactose monohydrate, or any ingredient/excipient in the placebo capsule.
• Known or suspected pregnancy.
• At risk of the development of unwanted pregnancy within the past 72 hours.
• Known, suspected, or history of cardiovascular, metabolic, or musculoskeletal disease.
• Undiagnosed abnormal vaginal bleeding.
• Use of anti-HIV drugs, anticonvulsant drugs, antibiotics, rifampicin/rifabutin, ulipristal acetate, Griseofulvin, Hypericum perforatum (St John's wort) or any other drug that may interfere with the normal pharmacokinetic or pharmacodynamic characteristics of the study intervention.
• Active or history of migraine.
• A condition or factor that would prevent the use of Plan B®.

Sponsors & Collaborators

• McMaster University: lead

Study Sites (1)

Vascular Dynamics Lab

Hamilton, Ontario, L8S 4L8, Canada

RECRUITING

MeSH Terms

Conditions

Venous Thrombosis

Interventions

Levonorgestrel; Gelatin

Condition Hierarchy (Ancestors)

Thrombosis; Embolism and Thrombosis; Vascular Diseases; Cardiovascular Diseases

Intervention Hierarchy (Ancestors)

Norgestrel; Norpregnenes; Norpregnanes; Norsteroids; Steroids; Fused-Ring Compounds; Polycyclic Compounds; Scleroproteins; Proteins; Amino Acids, Peptides, and Proteins

Study Officials

• Mark Crowther, MD, MSc, LLM, FRCPC, FRSC

  McMaster University

  PRINCIPAL INVESTIGATOR

• Maureen J MacDonald, PhD

  McMaster University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jenna C Stone, BSc

CONTACT

905-525-9140; stonej1@mcmaster.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 26, 2026
• First Posted: August 12, 2026
• Study Start: July 22, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: August 12, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)