Ok so yesterday at my 38 week appointment the doc said that I'm 2 cm dilated but the baby is still at -2 station, so pretty much doesn't want to come out yet, but she was a little concerned about his size because when she palpates my abdomen she says he feels quite large. So she said she wants me in for an ultrasound to check on his size. But I have heard from a lot of my friends who have had babies that this is really inaccurate like can be off by one or two pounds either way, so if its so inaccurate why would be the reason for them doing it? Is this done a lot around 39 weeks?