YMMW, but FWIW. You no longer have the luxury of hours-long uninterrupted coding streaks, but it doesn't prevent you from thinking through things that need to be done (e.g. when you are walking outside with a stroller). The net effect of it is that when you do have a chance to sit down and code, you produce something that requires no rewriting or refactoring later on. If you then compare time it takes to get X done, the think-then-code comes on top of code-then-rewrite and by a large margin.

In a sense having a baby forces you to become a more thoughtful and effecient programmer :)