I suspect it just means your baby is fairly short, I don't think anyone
calculated the ratios for either of my children, but the first had
particularly short legs, but with a normal or even big head, so the ratio
must have been out of the normal range. At the time I did search around for
any info I could find and there didn't seem to be much and no particular
cause for concern. My son was born at 37 weeks, he was short and skinny, but
for his gestation actually had an above average head circumference! He's
nearly 3 now and is still in the same proportions, which causes difficulty
in getting clothes to fit, but that is all. Sweaters and t-shirts that fit
his body are difficult to get over his head and as his height is comparable
to an 18 month old, trousers that are the right length are too wide as he's
not in nappies.

I suggest you ask your doctor what he thinks, the only concern I would have
is that it may be an early warning of a growth problem and therefore may
need extra monitoring, we think my son had that which was partially why he
was born at 37 weeks (he was induced), his weight was 5lb13oz.

Good Luck

Anne