I know when my children were young, I intentionally put my career on hold. I just instinctively knew I couldn't handle both, and my children were my priority. But I also don't think we should become martyrs to motherhood either and I recognize that taking a break or reducing your involvement can limit your future success.
I often compare starting a business with motherhood. It is almost as if there is a code of secrecy. No one wants to tell you what it is really like. No one wants to spell out the down times. The sleep deprivation. The sense of rejection when no one calls you. And no one wants to admit that it was less than perfect for her.