Pregnancy and blood types or subtypes

Some time ago I read an article online about blood types and their effect on pregnancy. I can’t find the article now. It would have been in the last 18 months or so. Of course, now I can’t find the stupid thing so I’m asking The Teeming Masses if you know what the heck I’m talking about.

The point of the article was that there are other … I’m not sure what word I want here, but let’s say, subtypes … aside from the well known AOB and Rh typings, and that, incompatibilities between these lesser known sub types may also negatively impact pregnancy.

I believe this is related to a new discoveries about the genetics and proteins that make up blood cells.

Hopefully, are medical and scientific Dopers will have heard something about this.

There have been a couple of threads in the last year or so that discussed hemolytic disease of the newborn. Is that what you’re remembering?