toptramp - I didn't! I gave up my job as a lecturer completely when DD was born, and I haven't been able to get back in. I've always worked in part-time casual jobs for pin money, but I never thought I'd find difficulty getting some kind of reasonable work once dd was older.
In my experience, you have to have a lot of support to be able to manage even a part-time job properly, and only then if have been able to hang on to your job and negotiate your hours down to suit.
The worst thing for me has been the slow decline in confidence and self-esteem. I now feel worthless and overlooked, even though I've got a faultless CV. Like many, I validated myself through work (perhaps too much so!) and found it difficult to adjust to domestic life.
On the plus side: being older (now 50) means that I have had a reasonable career, and was well-established enough financially to take a break. Also, it has meant that I have never needed to struggle with childcare!
It has also meant that I have been able to help others out with their DCs and deal with family issues such as bereavement etc without feeling compromised.
I'm still not sure if I've done the right thing, though! Good luck to you.