Consistently measuring behind

Anyone measured behind consistently and their doctor or midwife never seemed concerned or anything? Just had my 36 week appointment and I measured at 34. This isn’t the first time, at 28 weeks I measured 27, at 32 I measured at 30.5 and then 36 I measured at 34. So I’m consistently measuring behind and as time goes on I become more and more behind. My doctor didn’t mention anything about it or anything. I’m just worried they aren’t taking it serious or missing something. Any advice is welcome.