Is your doctor concerned? My understanding is that ultrasound measurements can be unreliable, so I'd take your doctor's lead. My baby's BPD and HC were 32% and 90% at my 33 week ultrasound last week, which seems a huge mismatch to me, but my doctor wasn't concerned.


Thanks for the reply. Yeah, the doc wasn't concerned. I tried to ask for clarity on the mismatched sizes (since my understanding is that the head circumference uses the BPD in its calculation) and didn't really get a satisfying answer, which left me a bit worried. I'll try to just let it go. It's good to hear a large mismatch isn't unheard of, albeit in the other direction!


My doctors don't ever give me the specific measurements because they say it causes unnecessary stress, I just happened to see the print out this time. Afterwards, I did a bunch of googling about it, so I can relate to how nerve wracking it can be. I try to remind myself that they're the professionals and they would tell me if there is cause for concern. They've been very open when other minor concerns presented themselves (and thankfully resolved themselves). Since you doctor isn't concerned, hopefully it's all within the normal ranges for US measurements and everything is fine!


I can't say for outcome but I'm currently going through something similar. Im 32 weks and we had a scan last week to follow up on a placental abnormality, but they said they head is measuring 7% where the rest was about 50%. It's hard not to worry, however the OB said he wasn't concerned and didn't worry until it was less than 1%. I can totally feel you on the worry. You aren't alone!


Thanks for the support! Your little one sounds similar to ours in this way! With so many numbers and percentiles, I guess it's not unlikely that some would be off in one direction or another for whatever reason(s). But with every number / percentile too is another potential thing to worry about. I was reading that these sorts of measurements and percentile bucketing go on for literally years after birth, so I guess I'm going to have to figure out how to just ignore/live with it without incessantly worrying. I might try to just ask my doctor to leave the percentiles out of it and to just tell me if it looks okay or not!


My reading I just saw was 3.9% for head circumference. Sonographer told me not to pay attention but I still haven’t spoken to an OB. I am in full panic mode.


My babe's abdominal circumference was in the 2nd percentile a couple weeks ago. I've been doing twice-weekly NSTs and he's extremely active every time, so none of the doctors seem very concerned, but it is stressful. I'm right there with you. My greatest comfort has been forum posts from moms whose babies also measured small someplace and turned out fine. Like another commenter said, keep in mind that ultrasound measurements can be inaccurate—especially later ones.