Overview
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:
- What is the short-term affect of Plan B® affect on the venous system?
- 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:
- Undergo baseline measurements of venous thrombosis markers, blood pressure, and measures of arterial function using ultrasound.
- Be randomized to either take a Plan B® or placebo pill
- 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.
Eligibility
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®.
