Fetal Limb Length Discrepancy

Jane Foley's picture


Dear Ms. Ultrasound,
Recently I had an ultrasound. it showed following results:

BPD 9.16 cm,
ABD circle-32.98,


There is discrepancy of 4 weeks in fetal age according to limbs measurement and other body parameters.

Please tell me what is it? in a corner written (small limbs). I had also bleeding in start of pregnancy." is all normal?


Hello, Limb shortening demonstrated on an ultrasound can be a cause for concern when the findings show a 4 week discrepancy. First let me make sure that the discrepancy is between the head and abdomen measurements vs the femur (thigh bone) measurement.

If these are off 4 weeks, meaning the head/body measures (lets say) 30 weeks and the femur measures 26 weeks, this is called limb shortening.

If the discrepancy is about slow symmetrical growth of the baby, that would be a different issue.

Please note that, Limb shortening may be noted in 4-5% of NORMAL fetuses.

Limb shortening can also be a finding in some chromosomal abnormalities. Because of this risk, a thorough Level II ultrasound should have been done to assess the babies anatomy, heart, fingers etc. If there is a chromosomal problem, there are usually other findings that may direct your doctor in making a diagnosis.

Once there has been a good look at the baby and it's anatomy, you will be monitored in short intervals with ultrasound to assess growth.

Your doctor should be able to walk you through all of this. Don't forget to ASK questions of your doctor if you don't understand a finding or explanation of something.

If you have any further questions just let me know.

With regards,
--Jane RDMS