According to Lydia Maria Child in her book Authentic Anecdotes of Slavery an enslaved mother beheaded her children in 1834 rather than have them sold away from her. This was before Margaret Garner committed a similar act in 1856, and was immortalized in a fictionalized account of her experiences recounted by Dr. Toni Morrison in her book Beloved.
The following case occurred towards the close of the year 1834, near Palmyra, Marion County, Missouri.
A slave-trader, who was making up a drone for the Red River country, bought three little boys of a planter. They were to be taken away the next day. The mother of the children was, in the mean time, chained in an outhouse , to prevent any troublesome interference on her part. During the night, she contrived to break her fetters and escape. She went directly to the place where her boys were sleeping–took an axe–chopped off the heads of all three–and then ended her own life by the same instrument.
The planter and the slave-trader, whose unrighteous bargain drove the wretched mother to this act of desperation, disrupted, and went to law about the price of the poor slaves!