Sahih Bukhari Volume 001, Book 009, Hadith Number 486.
Narated By 'Aisha : Do you make us (women) equal to dogs and donkeys? While I used to lie in my bed, the Prophet would come and pray facing the middle of the bed. I used to consider it not good to stand in front of him in his prayers. So I used to slip away slowly and quietly from the foot of the bed till I got out of my guilt.