This study will examine the combined effects of a continuous oral contraceptive (OC) regimen with supplemental estradiol therapy on headache severity and occurrence in subjects with documented Menstrually Associated Migraines (MAMs). The subjects enrolling in the study will have cyclic menses either due to spontaneous ovulation or use of cyclic hormonal contraception (pill, patch, or ring). Enrolled subjects will start a continuous OC regimen following two baseline menstrual cycles. If breakthrough bleeding/spotting (BTB/BTS) occurs, the subject will institute a 4-day hormone-free interval (HFI). In an attempt to prevent/lessen the severity of headache during the HFI, subjects will be randomized to oral estradiol or placebo during this period. If no BTB/BTS occurs after 80 days of continuous pills, the subject will institute a 4-day HFI during which they will be randomized into estradiol or placebo groups.

The purpose of this research study is to examine the effects of continuous oral contraceptive pills and oral estradiol on headaches that occur around the time of your period. Many woman take continuous oral contraceptive pills (OC) and when OCs are stopped they may get headaches. This study will examine if taking estradiol around the time of the period will affect the headache, and how it will be affected.

This study is a prospective trial. A subject's participation will last approximately 32 weeks.

Inclusion Criteria:

• Women may be on birth control pill (OC), patch or vaginal ring taken in the traditional 21/7 or 24/4 manner, which means that every month they have a period. If they are taking it continuously (without a period), you must be willing to take your birth control 21/7 for 2 months.
• If you are not on OC's, patch or vaginal ring you must have a period every 21-40 days.
• You must not want to get pregnant for 12 months.
• Women who have headaches around the time of their period.

Exclusion Criteria:

• BMI >38
• If you smoke and are age 35 years old or greater or if you are under 35 years old and smoke over 10 cigarettes a day.
• If you have or had an aura with your headaches. (An aura is a temporary sensation, like bright lights that come before you experience the headache)
• Headaches are not occuring during the time of your period.
• Blood Pressure > 140/90 or you take more than a single antihypertensive medication (excluding diuretics) and are age 40 or greater.
• Contraindications to combination estrogen/progestin hormonal contraceptives.
• Desire to become pregnant in the next 12 months.
• Stroke
• Breast Cancer
• Blood clots in your legs, lung or anywhere else in your body.
• Diabetes Mellitus
• Heart Attack
• Liver Disease
• Systemic Lupus Erythematosus