Apparently, checking the height of uterine fundus with a tape is a wooly practice but gives a rough idea as to whether the baby is growing. At 29 weeks, I think her bump should be 9 cms above her belly button. This all depends on when she last saw her midwife though, if she saw her three weeks ago and the bump seems in the same place then maybe it is cause for concern but if she hasn't seen her for 8 weeks and the midwife feels it just hasn't grown enough, then there's probably less need to worry. Either way, she'll either get this new scan and everything will be ok or she will just have to go back for more scans. I am predisposed to having small babies so had to have more scans than usual. Both my children were born healthy. This could also indicate that the baby is in a breech position though.