For me there were a number of considerations. I had my kids really close together so there was not really time for me to go back to work before I was again pregnant and I knew it would be hard to find work. My youngest is now 8 months and I have started working part time from home.
At the begining it was also a financial decision as I work in the not-for-profit sector so the amount I would earn, would not make it worthwhile to have full-time child care.
We now have a live in au-pair and that is great for when I go out to meetings but I mostly have meetings now in the evening so the kids are in bed. Once all 3 kids are at school, I will definetly go back to work but for now I am really enjoying the time with them and at the end of the day, being a mother of 3 is a full time job!
Good luck.