How Many Children Had Lady Macbeth? is the title of an article that famously argues that speculation about characters outside of what the fiction tells us is futile in criticism. In Shakespeare it can lead to the bizarre insistence that there is an underlying reality, a true interpretation, to be uncovered. But in theater, that kind of speculation is just the backstory; it's just what actors and directors do need to know to give the characters life.
I usually think how I'd depict something when I read the plays; in fact, it's hard for me not to push students toward my own favored images and stick to soliciting theirs. If I produced Macbeth, I'd make use of the fact that we know Lady Macbeth has had at least one child, though we see and hear nothing of their children in the course of the play (despite the fact that the sons of every other major male character figure in the plot). I'd covey the death of Macbeth's son or children, maybe by setting I,7 by the graveside--the moment Lady Macbeth urges Macbeth to kill Duncan. Then when she says,
I have given suck, and know
How tender 'tis to love the babe that milks me;
I would, while it was smiling in my face,
Have plucked my nipple from his boneless gums
And dashed the brains out, had I so sworn as you
Have done to this.
That would covey--in very melodramatic fashion, but the play is full of over-the-top touches, so it's in keeping--the real horror Macbeth feels when he hears this from her.