Do you not mean that your placenta is "anterior high"?
If so, then all that means is that your placenta is on the front of your uterus, at the top. It's important to spot low lying placentas & so many radiographers often put the exact position of the placenta on their reports.
It doesn't mean anything at all sinister, but it *might* mean that you don't feel lots and lots of kicks out front as the placenta kind of "muffles" the kicks. However, you should still feel the same amount of movement internally. I had an anterior placenta with Harry (my only pregnancy to date, so have no real frame of reference) and I still felt his movement early and had lots of them until he was born. I would worry at all at 23+4 as the baby is still very small, but certainly after 34 weeks you should be getting at least 10 movements in a 24 hour period, if you don't then it's important that you seek advice.
HTH's
xxx