One of the things I have seen come up a lot in anti-corset arguments is maternity corsetry.
I've seen it bandied around that maternity corsets caused birth defects and miscarriage, this seems in most cases to come from a complete misunderstanding of the purpose of a maternity corset.
The misunderstanding is that corsets were worn to appear thinner (which in the majority of cases wasn't true even for someone who wasn't pregnant), and as thus a maternity corset would be tightly laced, squash the abdomen and the fetus inside.
The truth however is that maternity corsets were, much like maternity bras and those super elastic-y maternity pants were support garments and not supposed to be tightly laced.
I've seen a couple of different kinds, , one kind looks just like a regular corset, but there are two extra lacing panels that you can lace looser as the pregnancy goes on, I do think that kind looks somewhat awkward and uncomfortable, but I have never been pregnant or worn it.
Another is the type like above with boned sides and and elasticated front.