In 1853, Victoria gave birth to her eighth child, Leopold, with the aid of the new anaesthetic, chloroform. Victoria was so impressed by the relief it gave from the pain of childbirth that she used it again in 1857 at the birth of her ninth and final child, Beatrice, despite opposition from members of the clergy, who considered it against biblical teaching, and members of the medical profession, who thought it dangerous. Victoria may have suffered from post-natal depression after many of her pregnancies. Letters from Albert to Victoria intermittently complain of her loss of self-control. For example, about a month after Leopold's birth Albert complained in a letter to Victoria about her "continuance of hysterics" over a "miserable trifle".
Hysteria and loss of control after the birts of many of her children were likely caused by what?
post-natal depression
The context directly states that Victoria may have suffered from post-natal depression after many of her pregnancies. 
It also demonstrates the symptoms she displayed due to this condition, such as hysterics and loss of self control..