Where are you in WI? I'm from WI too!
Since I've never been pregnant I really can't relate to how your instincts have changed around horses. But I think there might be a few things you can work on a few minutes each day to help set your horse up for success (and improved ground manners).
Let's focus on tying. Start by teaching your horse a head down cue. Downward pressure on the lead rope should be enough to get her to put her head lower. I always use a rope halter as it provides for much clearer communication to the horse. Spend 2 minutes a day working on "head down". At first she won't know what you want and may try to raise her head or look around, but keep the downward pressure on the halter until she lowers her head, even if it is just a bob of her head. Release all pressure the instant she gives into it. At the start of this process, she'll only keep her head lowered for maybe 1 or 2 seconds, keep asking for her to put her head back down. Eventually she will learn to keep her head in that lowered position and then you can ask her to put is even lower (and expect her to hold it there).
When you have the head down cue perfected (should take just a few days to a week if you give her 2 minutes of your time each day), then you can start tying her. She must be tied to something very sturdy that isn't going to break. You can have a hay bag for her, but I usually don't. The best part about teaching a horse to tie is that you really don't have any work to do (if you've prepared the horse properly). Still using the rope halter, and other equipment that won't break, tie her securely with about 18" between the knot and her halter. Give her enough room to move around and look about, but not enough room for her to get into trouble. Then step back and go about your normal activities. You should be able to expect her to stand tied quietly for any length of time without putting up a fuss. That would be your ultimate goal, but at first it may seem like you'll never get to that point. If she starts fussing, leave her be. She already knows how to give into pressure from the rope halter (because you taught her the head down cue), let her figure that out again on her own. Her fussing may get worse before it gets better. She has to work it out by herself. You can reward her (by untying her) when she is standing quietly and relaxed. She might thing this tying thing is no big deal and after 5 minutes you can put her away. Or she might think that she's got to do whatever she can to get back to the other horses eating grass in the pasture....if that's the case, she'll be waiting all day (or until she settles down). After a week of tying her, she should be pretty good about it and I bet her other ground manners will be improved too.
You'll find that I don't like using gimmicks or quick fix ideas. I've used these methods on my own horses for many years. My 3 yr old will even stand tied - or rather, stand sleeping! - at the trailer all day at a horse show all by himself without any fuss. (I have to tip toe to the trailer so I don't wake him up!