My 10 wo was consistently gaining weight in the 75th centile, but when I took him to be weighed last week he'd dropped to the 50th centile (gaining 2oz in 2 wks). I took him back this week and he'd gained 5oz, but is still in the 50th centile. He's alert and happy and has lots of wet nappies and at least 1 dirty nappy every day. He seems to be consistently feeding, although he's had a cold and his blocked nose is causing him to fuss. The HV said she couldn't find an answer and said babies do go up and down, but I can't stop worrying about it. Has anyone else experienced similar?