Atherosclerosis, Immune Mediated Inflammation and Hypoestrogenemia in Young Women

Study Aims: 1. To test the hypothesis premenopausal HypoE (women with FHA) is associated with pre-clinical CVD as determined by reductions in vascular endothelial function. 2. To test the hypothesis premenopausal HypoE (women with FHA) is associated with increased immune-mediated inflammation. 3. To test the hypothesis whether estrogen replacement can reduce inflammation and improve vascular endothelial function in premenopausal HypoE women (women with FHA). In a randomized, double-blind placebo-controlled trial in premenopausal HypoE women (women with FHA) the investigators will test 12 weeks of transdermal estradiol 0.1 mg/day patch or placebo followed by 2 weeks of estradiol plus progesterone 200mg (for endometrial safety) on vascular endothelial function and immune-mediated inflammation versus placebo. Patches will be applied by the participant to the lower abdomen twice weekly, alternating sides. The investigators will be using non-invasive tests to measure vascular function to measures reactive hyperemic index (RHI) using peripheral arterial tonometry (PAT)