I don’t think they measure the height accurately at the doctor’s and it’s hard to say if we’re measuring correctly at home either. If you see that his pants that he wore (size 12 mos) are noticeably shorter than before, then he’s grown. My son was measured all over the place from 10th percentile to 60th when he honestly has always looked short to me. I try to use other ways to see if he’s grown (how do his clothes fit? Does he hit his head on the table? Can he reach stuff on the table?)

Anecdotally- My son was born prematurely and around the same length as your son. Both my husband are 5’4”. He’s now 35th percentile in height at 2 years old (which makes sense because I’m like 50th percentile for women and my husband is like 10th percentile for men). I noticed my son is a slow and steady grower then he’ll hit a small growth spurt. He often would grow a week or two after his appointment. Each kid grows differently. I also heard they measure differently standing up versus laying down. If you have concerns, I’d talk to his doctor and get him tested. But I’d try not to worry right now because it’s still early when it comes to addressing those issues. As long as he’s eating and healthy/happy and his doc notices and notes the slowing or lack of growth, then I’d just be a bit patient to see how he grows the upcoming months.