In reply to Dave the Rave:
I guess that maybe, just maybe, a pregnant climber's going to have an unusually attentive belayer, and not exactly be lobbing off any leads after skipping a few clips. Flopping onto a tight top-rope in a preggers-specific harness is likely much safer for the bump than something more high-risk and unpredictable... like walking down a flight of stairs.
The 'sudden shock to the body' (and more specifically the kiddo) is probably greater when slumping into a sofa, given likely distances travelled and deceleration forces involved.
I think if I'm following your logic fully, that we should all get brain damage every time we fall (and are presumably, stopped by a dynamic rope) while climbing. Our heads are, after all, attached one way or another to our legs, abdomen and back. The shock, as you say, goes all through our body, including our brains. Luckily the brain is nicely contained in a bag of juice, so it's nicely isolated from such shocks (and worse). My understanding is that before they hatch out, small humans also inhabit a bag of juice, so I guess possibly the protective mechanisms involved are similar to the ones which ensure we're not (routinely) brain damaged by everyday top-rope falls.
The original poster already said they're using it for top-roping. I'm having difficulty visualising a top-roping set-up where there are significant sudden shocks reverberating through the body.
I think for the situations which everyone else above seems to understand they're intended for, these kinds of harnesses are pretty obviously perfectly safe for all parties involved. I'm not questioning that they could definitely be misused for doing much less safe/probably unsafe things (E-grade trad leads?), but don't agree at all with your conclusion that they are by definition unsafe.