I would definitely wait. You will have time after the baby is born to put your resume together and start looking for a job. If you don't find one, you'll have a job to go back to. If you do, then you can start the new job after your maternity leave is over.
To be honest, the next several months, including your maternity leave, will be a time for people to get used to all the changes, and probably everything will shake itself out by the time you get back.
I was interviewing for a job with a friend of mine years ago. I found out that I was pregnant, and shortly after, the boss told my friend that she had to hire his daughter. I had not disclosed that I had found out that I was pregnant, and I was upset about her offer being rescinded because I wanted to get experience in this particular business. But after going through my pregnancy, I realized that I was SO lucky that I didn't get that job, B.. I had trouble in my pregnancy and my long-time job was very understanding. When I got back to work, I definitely had trouble getting back into the swing of things. I had to make lists for everything! I wondered what was wrong with me that I couldn't remember everything I used to remember. It took a while. I was especially glad that it wasn't with a new job and people who barely knew me.
I also would have hated it if my friend had been unhappy with my work. And what if she would have replaced me? It would have been very stressful on our friendship.
Now, I know that your situation would be different because it won't be your friend, but still, a new job while you're pregnant and right after you have the baby is hard. So if I were you, I'd hang tight until you have had this baby and get your paid time off.