Blood Pressure; Low as a possible prodrome or trigger?

I have seen mention of high blood pressure being associated with severe headaches. I am wondering if *low* blood pressure (110/60 or less) might preceed or accompany the onset of migraines for some people. If people are willing to collect personal data to see if there might be a correlation, it might be worthwhile to aggregate it. I am going to try this myself, although I recently have not been having as many migraine episodes as I used to. The way I will do this is to take a couple of BP readings at about the time I find it necessary to take an oral abortive like Imitrex, and compare that to baseline values after the migraine has been aborted by the meds and at other times when I have been free of migraines for at least 12 hours. For ease of recording, use a monitor that displays time and preferably also date, snap a photo with a phone camera, and record the data later.
Has anyone seen any published studies relating BP and migraines?