It can go either way - some women's blood pressure climbs, some goes down.
On the one hand you have increased pulmonary vasodilation, but on the other you have this (the 'long term' aspect may be relevant here):
Researchers have found that long-term estrogen exposure generates excessive levels of a compound, superoxide, which causes stress in the body. The build-up of this compound occurs in an area of the brain that is crucial to regulating blood pressure, suggesting that chronic estrogen induces a build up of superoxide that in turn causes blood pressure to increase.
My blood pressure, which was always a bit on the low side, has remained unchanged after one year on estradiol and anti-androgens.