I'm currently an M1 at NSU-COM and had a baby girl about 2 months before classes started. Let me tell you what my average week is like.
I usually get home (after picking up my daughter from a friend's house) sometime between 4 and 6pm. My husband and I play with her for a few hours til she gets tired and cranky around 7 or 8pm. During that time we also manage to make or order dinner and eat. After she goes to sleep I either study, spend time with my husband, or get caught up on other things (contacting friends, paying bills, etc). I make sure that at least 2/7 nights are spent entirely with my husband. On Saturdays I go to my mom-in-law's house for about 6 hours so she can spend time with the baby while I study. I get about 5 hours of productive studying done. Sundays my husband and I switch off spending time with the baby so I get about 3-5 hours of studying done. Total I average about 15 hrs of study time per week. Recommended amount is 30-40hrs. I could definitely get in more study time, but I already miss my daughter and husband SO MUCH as it is that I would rather get the grades I'm getting (A's/B's) than be the best in the class and not ever see them.
I'd say consider these things:
Do you have someone you TRUST to watch the baby during the week? Can you handle missing baby milestones like first words, steps, etc? Do you usually need to study more or less than most other people? Do you prefer to study in groups or alone (b/c it's hard to commit to group studying since babies are so unpredictable)? If you wait, how will you handle being pregnant while in school or residency(Did your mom have easy pregnancies)? What type of residency are you considering?
Since I'm only an M1 I don't know what second year is like, but I've heard it's a lot easier than first so it's probably a good idea to wait til then. My choice was to put off med school, not put off having a baby, which is a lot different. I felt better starting medical school sooner b/c I felt like I would rather miss the baby milestones (when my daughter is so young she won't be disappointed) than miss things like dance recitals, soccer games etc later on when she'll need me more mentally/emotionally.
Anyway, feel free to PM me with any other questions. Good luck!! And remember, God only gives you what you can handle so whenever you get pregnant--that's the right time.