I have recently been told about two more female poets -
Akiko Yosano (1878 - 1942) a Japanese poet, whose most famous poem "Thou shalt not die" was dedicated to her brother and turned into a protest song - kindly brought to my attention by Yoshihiko Nakanishi
Austrian poet Ingeborg Bachman, kindly brought to my attention by Mike Lyons who, with Patrick Drysdale, has selected and translated some of Ingeborg Bachmann's poems into English in a book entitled "Ingeborg Bachmann enigma Selected Poems", published by Ariadne Press, 2011. Bachmann was born after the First World War but the fact that she was Austrian and grew up during the period between the two World Wars, means that she has a lot to say that is, in my view, relevant as we approach the Centenary of the First World War and look in particular at women's poetry.
My grateful thanks to Yoshihiko and Mike.