Hi Amanda,
Congratulations on your pregnancy! I hope you're doing fantastic and feeling as well as you possibly can be at this stage. Congratulations also on your impending graduation.
There are quite a few moving parts here. The one you're focused on right now is whether it will hurt you in the application process. But there are lots of others that you're not even aware of yet. 🙂
I'm going to try to help you through some of these moving parts, but I can't tell you what to do one way or the other. You have to decide for yourself.
I had a baby mid-October of 2011. Note: this was my third. Things are quite different on your third trip around the block than they are with your first (lol!). The school I'm most interested in attending is quite progressive, and has bent over backwards to demonstrate their family-friendly policies, that they value non-trads, etc. This varies a great deal by school. FYI--UNC is probably among the most progressive medical schools in the country in this regard, but I'm very interested to hear about others' experiences as well.
If I were you, my enormous concern would be the interview season itself. It sounds like you're due at the end of December, which means your little one could arrive anywhere during December and the first half of January. Depending on the timing of your due date, you're definitely not going to be traveling after Thanksgiving. Depending on how things go, you may be cutting it close to go more than a few hours from home after October.
YOU WILL NOT BE ABLE TO TRAVEL COMFORTABLY FOR AT LEAST SIX WEEKS AFTER THE BIRTH.
I put that in all caps because I'm not kidding. I headed back to classes a week after my newest baby was born, but as I said previously, things are different with your third gremlin. Once you're released from the hospital, your doctor will prohibit you from driving for two weeks. People can and do travel sooner, but I definitely wouldn't have any delusions about being able to do it. It's much, much different giving birth and recovering from subsequent pregnancies than your first. It's much, much different caring for a newborn once you've gotten good experience with your first.
All of this is to say: in my extensive experience being pregnant, having babies, and balancing work/school/family, your problem is not going to be judgmental/biased interviewers. Your problem is going to be getting to the interviews in the first place. Because you're going to be ripe for the picking smack in the middle of interview season.
Regarding discrimination, judgmental attitudes, and bias--they are definitely out there. As I mentioned before, this varies by school. I don't think anyone would intentionally discriminate, but most of America doesn't seem to feel like it's discriminatory to refuse jobs to pregnant women, fire them for having to go to doctors appointments, or tell mothers that they can't breastfeed/pump if they want to work. Take from that what you'd like.
The other thing to consider is that you don't know how your pregnancy and delivery will go. In a few months, you may develop complications that make traveling for interviews (pre or post-delivery) a moot point.
Also consider what you'll want to do after the baby is born. Your baby will be 6+ months by the time you matriculate and begin classes. That's a great amount of time for rest, relaxation, and then to get back into the swing of things. That said, assuming you don't hear back until the first of May, you don't have long to find a place to live, move, and arrange childcare. Everyone is different, but that is not a nightmare I would want to live (lol!). Also note that you'd be leaving your support system behind if you move. First baby, starting medical school....that's a lot of change in a short time. It might not be wise sever yourself from the strong support system you have in place right now. I promise--you're going to need it (hahaha!).
I feel terrible at this point, because I feel like I'm coming across as a Debbie Downer on this one. Please know that this is not my intention at all. If you decide to apply, I'll be rooting for you, and will check back often to see how you're doing. Besides your husband and family, I'll be your number one cheerleader. Being a mom is an impossible job, but I know you'll do great at it. Whatever you decide, I *know* you'll make the right choice for you.
Now, navigating interviews...
I can see a few options here. Apply early decision, and get that interview out of the way early on. I'd definitely suggest calling schools, and asking them directly how they would handle this. If you can get your AMCAS application in fast (ie, June 5-June 29) and get a good turnaround on secondaries, you have good odds of scoring an early interview. Here again, it never hurts to call, explain your situation, and ask/beg for one of the first interview slots.
Finally, talk to your doctors. I found my ob's to be incredibly supportive. They were huge cheerleaders, excited for me, and eager to help out anyway they could. They were a major encouragement.