Hi - I was taken off the pill at 49 because 'new rules' had come in that mean you can no longer take COC if you have ever had a migraine with aura. This was after a study which showed there is an increased risk of stroke if you have migraine with aura.
This risk, combined with the (very small, but it is the
only risk for a lot of young people) increased risk of stroke of COC, resulted in guidelines that meant you could no longer go on the pill if you have ever had a migraine with aura. There has been a lot of publicity about young girls who die of a stroke shortly after going on the pill which has probably added to this.
The pill is given to healthy people who just want to stop pregnancy, so I guess the risks outweigh the benefits.
http://www.fsrh.org/pdfs/UKMEC2016.pdf (page 71)
COC is a very high dose of progestogen and about 30mg of a synthetic oestrogen (I don't think the actual dose is that high in the low dose pills that have been around for the last 30+ years, but it is one that has a strong effect on the switching off ovulation without breaking down too fast).
The guidelines are not the same with hrt and I have been on that for the last 2 years.
(I have only ever had auras without the 'migraine' since my teens, anyway)