BPD measures 4.48cm which is <2% percentile - measuring 19weeks

But his HC is 17.5cm 46% percentile - measuring 20w6d

BPD = Bi Parietal Diameter. HC = Head Circumference

Cerebellum 2.11cm 32% percentile - measuring 21w2d

AC is 17.1cm 76% percentile - measuring 21w5d

But he also has very long legs apparently! FL is 3.87cm >90% percentile measuring 22w3d

Mostly concerned about the BPD but I thought if that was small the HC would be small?

Thanks in advance for any info!