I have a dear friend who lost her job and was out of work for some time before finding something new. She and I used to be quite a lot alike in that we had the same type of job, had the same type of spending habits, etc. That was before my husband and I decided that we would try to make it work on one income. I was trying to help her mood one day as she was having a hard time in her job search and she said "I feel like I am not contributing to the household when I am not working". It was innocent and truly how she felt, but it really struck a nerve with me as by default it made me think as though she thought I was not contributing to my own home.
I know that I contribute but I think our society has swung so far away from the idea of staying at home with children that it is not seen as a contribution to the home. Even if you don't want to weigh in the emotional factors of a child being primarily cared for in a home environment versus a day care, there are some real cost factors that often times just don't add up.
Here is a site that shows an online calculator for you to input the cost of working after putting a child in daycare, and all the associated costs of having an out of the home job.
I entered some data reflecting the costs I had associated with my last job and added in the cost of day care in my area and I would be netting about $2.50 and hour, assuming that my job covered the cost of health insurance as the last one did, if it did not I would net about $1.00 per hour. This net pay would go up over time as the daycare for a young child is much higher than daycare for an older child. It just does not seem worth it to me, and I believe with the right amount of budgeting you can make up for the difference of what you would be bringing into the home.
Here is a series of articles about staying at home and making it on one income.
The cost of working http://homeparents.about.com/cs/familyfinances/a/workcalc.htm
This decision is not easy, and is different for every woman and every family, but I hope that the articles listed above can help in your decision.