Yeah, I know it sounds really strange to not know. It's an odd story, really. I did some research after I found out to figure out why there was confusion and I found some interesting facts. Apparently, soy can cause a false positive on the Rh blood test, which I was a 9 year vegetarian when my first son was born, so they thought I was A+ and told me so.
I had a different midwife for my other three, and I told her I was A+, so I don't know if she even tested my blood type, but I wasn't vegetarian by that point, but still eating a LOT of soy products, so it could have still been affecting the test. If not, then I have absolutely no explanation why they didn't find it with baby 2 and 3.
Baby 4 was the one it came back -, and my midwife actually redid the test three times because she didn't believe it. The lab told her something about a new test that was way more sensitive, so apparently I have Rh- blood. I thought I was just a freak of nature and my blood proteins mutated or something. But after no cool X-men abilities developed, they just monitored my antibodies. Baby 4 was Rh +, but had no complications. I don't know what type the other 3 have, or this baby, obviously. They did do bloodwork about a month ago, and she either said antibodies were non-existent or low, I can't remember.