“The Death of the Ball Turret Gunner”

I really don't understand what this poem is about. The first two sentences seem to be talking about a pregnant woman or something, then it goes on talking about flak and fighters, which is kind of a war or military thing and I am completely lost from there.

Well, after we saw the footage of the poem, I have a different view to the poem and now I understand what it is about. It is about a soldier inside the aircraft in small spot called Ball Turret. They are at war and he is in charge of using the Ball Turred. It's freezing in there and he is not really comfortable because the Ball Turred is spinning.