The only thing I might add is this.
Heather said something that I found interesting.
Your body responds to this kind of impact by focusing resources on you arms and legs. I wanted those resources to go to my growing baby.
There's a lot of work that's been done trying to figure out how and why various kinds of conditioning works. Back when I was constantly trying to get stronger/bigger and was shadowing my wife and her own bodybuilding experience, I used to do a lot of reading in the field.
When you are training, there is a global as well as local training effect. In other words some kinds of intense training is followed by release of both growth hormone and testosterone. These are anabolic or building hormones. If you overtrain however, the body releases a catabolic stress hormone called cortisol.
When you are training properly, you feel better. When you are overtraining, you feel run down. Both men and women comment on improved disposition, libido, etc. when they are working out properly. Too much can lead to an increase in colds, run-down feeling, etc.
So what does this have to do with anything? Well... My wife had extraordinarily healthy and robust babies. She was really funny... She would look in the nursery and say "I win!! Take a picture, Bill! Look how big he is compared to all those other scrawny babies!" Talk about competitive...
But seriously... She had been training for years, and understood how to get just the right training effect. So when she was doing squats or curls or flies, some of the anabolic hormones she released (IF she wasn't overtraining) were going to junior as well. Train properly? Baby benefits. Live like a slug or otherwise treat your body poorly? Baby loses. Overtrain? Baby loses.
I don't have all the data to back this up, but I would think the same would hold true for some of our karate training. Light kotekitae that builds and doesn't bruise very well may benefit junior. The same hormones that stimulate tissue growth at point A will go to point B to some degree. This of course assumes that you are eating a balanced diet and getting proper rest. Overtrain to the point of releasing cortisol, and baby loses as well to this stress hormone.
It is worth mentioning that Heather is viewing all of this from an entirely different health paradigm. She's an accupuncturist by profession. So her world of "stimulating" the body involves a different view. She could articulate that better herself; it isn't my training or my own paradigm. Enough said.