Today I took K to the doctor and he told us her head was flat on one side. I know about Positional Plagiocephaly from naivete's post and from that I learned that I shouldn't let lay on her back too long, and I don't, or at least I try not to. She favors laying her head on one side over the other and I try to get her to lay her head on the side she favors less, but regardless how many times I adjust her head she puts it back in her favorite position. I also try to give her tummy time, but whenever I put her on her stomach she begins to cry. I've tried sitting her in her bouncer with a towel rolled up and propped against the side I don't want her to lie on but even that doesn't work. I don't know what else to try does anyone have any ideas?
It could be something caused by shortened or weakened neck muscles on one side. I forget what it's called. When you hold her in a sitting position does she always tilt her head to one side? You could pm naivete, I'm sure she'd be able to tell you more about it.
It's called torticollis, it's a disorder which often causes plagiocephaly if not treated.
A lot of the times it's caused by a muscular disorder, in which one of the muscles in the neck is either too weak or too short to properly contribute in moving the head, so the other side's muscles take over. It could also be caused by (rarely) vision problems, bone abnormalities in the spine, or a neurological imbalance, but most often it's caused by a muscular condition in the neck.
If the plagiocephaly condition of your daughter's isn't treated, it can cause a lot of things, but mostly a permanent skull disformation, sometimes affecting brain growth, eye sight, jaw disorders, etc.
Torticollis though, if not treated, can effect a lot more. It can cause a permanent limitation of neck movement, it's best to get it treated while she's still young, because at this age it can still be corrected through exercises and equipment, whereas when she's older, it would have to be corrected through surgery.
See http://www.pedisurg.com/PtEduc/Torticollis.htm for some simple diagrams on stretching exercises that you can do to help it, although I'd recommend getting a referral to a neurosurgeon or neurologist in your area for more definitive treatment for both the torticollis and plagiocephaly. You can find one in your area by going to http://www.plagiocephaly.org/ppcs-location.asp and doing a search by location. Your normal doctor or pediatrician is NOT qualified to do any diagnosing, the only thing they're qualified to do is refer you to someone who specializes in it.
I'd also suggest visiting the yahoo group I belong to, there's about 5000 members of the group and there's many hundreds of women there who've been through plagiocephaly caused by torticollis, or just torticollis on it's own, that you can talk to for support, help with exercises, suggestions, and other things you can do.
http://health.groups.yahoo.com/group/Plagiocephaly
Torticollis does need to be treated though, if you have any other questions, a need for other resources, or need any help getting the ball rolling, please PM me and I'll be glad to help in any way that I can.