WHAT DOES LADY MACBETH SAY SHE WOULD DO WITH HER CHILD IF SHE HAD TO?

Lady Macbeth says she would have smashed its skull against a castle wall if she had to.

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.