Since no MBA moms answer the question, I will try to give some perspective based on my observations. Even though it seems like it is going to be easy to find 2-3 hours daily for school work based on your current job situation, once you have a baby the picture will change dramatically.
I remember seeing in the past some posts from one MBA mom on this or some other MBA forum who managed to have a baby during her school. She was doing a full-time program though. She was juggling two major commitments: MBA and the baby, I believe in that order. She also seemed to have huge support from her family. You however, will have three commitments: MBA, a job, and a baby.
Everything is doable, but the question is at what cost. Sometimes it is perceived that part-time MBA is less time challenging than the full-time program. It is true in a sense that you are not required or expected to participate in as many extracurricular events. However, academically it will be the same load. You will be pressed for time and you will be torn apart between the school and the baby. You will have to rob one experience or the other. And it may be a grueling choice to make on an ongoing basis.
In my three years of part-time MBA at GW I don't remember a single lady who had a baby during the school. I know of at least four guys who had a baby in the family towards the last year of the program. Did not ask them if their wives were housewives or had a job at the time. So if you have a complete buy in from your spouse and he is ready to become a "semi-single" dad while you are in school, it will be doable to manage it. Still, it would be advisable to wait until the end of the first-second year in the program that are going to be more challenging.
Speaking of the ladies, my married classmates started to pop up babies within the first year after graduation like champagne corks on the New Year eve
There are a lot of working moms who have babies, but from my observations the number of working women who go through the graduate degree and have a baby at the same time is disproportionately less.
Again, I am not a mom. I had two teenage daughters while doing my MBA and they were significantly deprived of my attention most of those three years.
Still waiting on some part-time MBA moms to chime in. Do they even exist?