Skip to main content
OpenTrials
Recruiting

NCT Number: NCT07759635

The Influence of Plan B® on Cardiovascular Health.

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. What is the short-term affect of Plan B® affect on the venous system? 2. What is the short-term affect of Plan B® affect on the health of arteries?

Researchers will compare a single dose of Plan B® (1.5 mg of levonorgestrel) to a placebo to see if Plan B® has unique effects on the cardiovascular system.

Participants will:

1. Undergo baseline measurements of venous thrombosis markers, blood pressure, and measures of arterial function using ultrasound. 2. Be randomized to either take a Plan B® or placebo pill 3. 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.

Recruiting

Interested in participating?

Request Info

Key information

Conditions

Female Cardiovascular Diseases Embolism and Thrombosis Premenopausal Thrombosis Vascular Diseases Venous Thrombosis

Age range

18 year–35 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Vascular Dynamics Lab

Hamilton, Ontario, L8S 4L8, Canada

Location status: Recruiting

Location contact

Maureen J MacDonald, PhD

CONTACT

[email protected]

905-525-9140 ext. 23580

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Provide written informed consent.
  • Pre-menopausal female.
  • 18 - 35 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.

Exclusion criteria

  • 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®.

Treatment and study plan

Plan B (Levonorgestrel)

Drug

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

Placebo (gelatin capsule)

Other

Gelatin capsule over encapsulated to mimic Plan B

Primary outcomes

  1. D-Dimer

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

    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.

  2. Prothrombin fragment 1+2

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

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

  3. Thrombin antithrombin

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

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

  4. P-Selectin

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

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

Secondary outcomes

  1. Brachial artery flow-mediated dilation

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

    Measured as the percent change in brachial artery diameter from baseline to peak dilation following reactive hyperemia (%FMD).

  2. Levonorgestrel

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

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

  3. Systolic blood pressure

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

    Measured in millimeters of mercury (mmHg)

  4. Diastolic blood pressure

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

    Measured in millimeters of mercury (mmHg)

  5. Mean arterial pressure

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

    Measured in millimeters of mercury (mmHg)

  6. Heart rate

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

    Measured in beats per minute (bpm).

  7. Height

    Time frame: Baseline

    Measured in cm using a standiometer

  8. Weight

    Time frame: Baseline

    Measured in kg using a weight scale

  9. Body mass index

    Time frame: Baseline

    weight (kg) / ( height (m) )^2

Study contacts

Contact information is provided by the study sponsor or research team.

Jenna C Stone, BSc

CONTACT

[email protected]

905-525-9140 ext. 27037

Sponsors and collaborators

Lead sponsor

McMaster University

Other

Registry information

Official study title

The Influence of a Single Dose of Emergency Contraception on Markers of Venous Thrombosis and Vascular Function in Young, Healthy Females.

Acronym: LEVOH

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Aug 12, 2026
Registry last updated
Aug 12, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.