My son is 8.5 months and has been a slow gainer since about 3.5 months...he's had periods of no gains, and periods of slight gains. He was in the 50th %ile when born, dropped to about the 30th at 4 months, 25th at 6 months, and is now in the 10th. At every visit my doctor said not to worry, he was finding his curve and would stabilise, but at the latest visit this morning, he hadn't gained much at all since 6 months and she was all of a sudden very worried. We need to go in for blood tests on Tuesday for thyroid and a few other things. She said she wouldn't diagnose him as failure to thrive yet, but by 10 months if his weight was still stalled she would.

Has anyone dealt with this before, and did things get better? What tips do you have on bulking babies up? He's on purees and chunky foods, isn't great at self feeding, and still gets 4 milk feeds a day (2 formula, 2 BF). He's crawling, pulling up, super active, STTN. Pretty much he's the best baby, super chilled and easygoing, but just doesn't seem very driven by hunger so its hard to force feed him.

Any advice?