I wasn't the CEO of the company I worked at, but Architect (and Director) and we were working on major overhaul of our product. My son was born right around the Release timeframe. All I could do was design and plan and prepare my team for any last minute emergencies. Like her, my energy levels in last 2 months also were not what I wanted. Everyone in my team had worked our asses off and I felt guilty of not being productive enough in last 2 months and being away right when they would need me if things went downhill. Many of the design decisions were mine and if things went wrong I did not want my team to be hounded by our customers and execs.
Being an employee who is responsible only for himself/herself vs. being responsible for a team(s) is different and if you were not able to time your absence in the right way, it feels even worse.
I have come to realize that our cultural norms have a big role to play in how we (females) treat ourselves. We don't expect/want any special favors at work, but we also expect ourselves to do everything our moms and grandmoms did. It's all about being able to figure out what makes us happy and work to achieve that. It took me a while but I know that I will be miserable if I did not work the way I do and that will not be good for my son either.
For me, it's dejavu again as I just learned today that I am 3 months pregnant. And I joined a startup 4 months ago, and we drafted up a release plan of our first major version to be 6 months from now. Go figure.