An interventional study of Plan B (Levonorgestrel) and Placebo (gelatin capsule) in Female and Premenopausal, sponsored by McMaster University. Recruiting at 1 site in Canada. Open to female participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-14.
Sponsored by McMaster University · Not applicable, Interventional, and Basic science
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:
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:
785 studies on the registry are indexed under Venous Thrombosis; 110 are open to participants now.
This study's planned enrollment of 40 is below the median of 152 across 477 interventional studies indexed under Venous Thrombosis.
Browse Venous Thrombosis studies →McMaster University is the lead sponsor of 741 studies on the registry; 127 are open to participants now.
Of its 7 completed or terminated interventional studies of FDA-regulated products, 3 (43%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
1.5 mg Levonorgestrel
Drug: Plan B (Levonorgestrel)
Gelatin capsule
Other: Placebo (gelatin capsule)
1 x dose of 1.5 mg levonorgestrel tablet over encapsulated to mimic placebo.
Gelatin capsule over encapsulated to mimic Plan B
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.
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
Prothrombin fragment 1+2
Measured in pg/mL from platelet-poor plasma using an enzyme-linked immunosorbent assay (ELISA).
Time frame: 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).
Time frame: 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).
Time frame: Baseline, 1-hour, 2-hours, 6-hours, 24-hours, and 48-hours post-ingestion of Plan B/placebo.
Brachial artery flow-mediated dilation
Measured as the percent change in brachial artery diameter from baseline to peak dilation following reactive hyperemia (%FMD).
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
Levonorgestrel
Measured in pg/mL from serum using an enzyme-linked immunosorbent assay (ELISA).
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
Systolic blood pressure
Measured in millimeters of mercury (mmHg)
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
Diastolic blood pressure
Measured in millimeters of mercury (mmHg)
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
Mean arterial pressure
Measured in millimeters of mercury (mmHg)
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
Heart rate
Measured in beats per minute (bpm).
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
Height
Measured in cm using a standiometer
Time frame: Baseline
Weight
Measured in kg using a weight scale
Time frame: Baseline
Body mass index
weight (kg) / ( height (m) )\^2
Time frame: Baseline
Plan to share: No
No publications or documents are linked to this record.
Started Jul 2026 (actual). Primary completion is estimated for Jun 2027, 10 months after the start.
Of 99 non-industry interventional studies with no phase under Venous Thrombosis, half reached primary completion within 35 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 57. This study's planned 10 months is below that.
Counting every sponsor, half of 117 studies reached it within 34 months; a quarter within 13 and three quarters within 56.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Levonorgestrel