I did 7 years as a SAHM mother and then went back to work. A lot of my early working life was spent making no money out of it. With 3 DC, the youngest profoundly disabled, the salary, CB and disability living allowance only just covered the childcare, and I had to take a job with a crappy commute in order for the pay to be enough. Even now, in my 50 s, ds2 still needs 24/7 care so I pay for childcare after school for a 17 year old, and it takes half my take home pay. Has it been worth it?
I help my GP train medical students, and one thing they always ask, is how come I am what they call "resilient" which is polite medic-speak for not depressed. A lot of my fellow mums at ds2s school are very low, and they feel their lives are very hopeless and restricted. For me, earning and having a career has been important for me to feel that I have some control over my life. It took a long time for me to make any money at it, but it has kept me happy and sane to have that other side to my life. And I will have a workplace pension, which will be much appreciated.
I chose to be a SAHM when my older kids were preschool and I still think there is a great deal to be said for that, educationally as well as financially. Once they are at school, even the most disabled kid is out of the house for 6 hours a day, whoopee, and then I found it very helpful to build a life for myself. But in the shorterm you will make no money at it. Though I do think that childcare is attributable to dhs salary as well as mine, in practice that's just not quite how it feels.