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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
40
1 x dose of 1.5 mg levonorgestrel tablet over encapsulated to mimic placebo.
Gelatin capsule over encapsulated to mimic Plan B
Vascular Dynamics Lab
Hamilton, Ontario, Canada
RECRUITINGD-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
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