Baby's femur is measuring short!! Need info!?

Question

Hi, I am 32 weeks pregnant, and 2 weeks ago, my baby's femur bone measured out to be in the 13th percentile, which is a concern because anything below the 10th is considered abnormal. His abdominal circumference is in the 77th percentile, and his weight was 3 lbs, 14 oz., which is a pretty good size! After researching online, I have read that a short femur could indicate down syndrome or dwarfism! All of my triple screen results came back negative, and so far all ultrasounds have looked great! I am only 5'0 tall, and my husband is about 5'10. So, he could just be short. If he had down syndrome, would I kind of know it by now or not necessarily? Also, has anyone experienced a baby with a short femur that ended up being normal???

Answer 1

The triple screen does not pick up everything, many parents of down's and dwarf's find out after the baby is here, there is also a lot of false positives too.  If they were concerned you would have been informed and sent to a specialist.  There are other signs of dwarfism, one being macrocephaly, and you don't mention a head in the 99th percentile, so chances are your baby doesn't have that additional sign.  Measurements are not that exact, especially so small, being off by a fraction on the measurement can make the percentile seem much lower or bigger than what it really is.

I did fail the triple screen with low levels indicating down's twice.  My oldest additionally had hard and soft markers for down's.  We did see a specialist, and were encouraged to have an amnio.  Which we did.  Personally it was not about keeping the pregnancy, he had a heart condition and the most info we could gather would be most beneficial in case surgery was needed, which it wasn't.  My oldest does not have down's, does have autistic features with the macrocephaly too.  Inutero though he had the heart defect, and 2 other marker's at risk for down's, one was the nuchal folds on the back of the neck, and the other had to do with the hand.  They were pretty sure he was down's till the amnio came back.  So even with 4 markers it wasn't so.  How many u/s scans have you had?  If you are getting them every week and it has never been mentioned about the femur size I would say its highly unlikely that the baby has dwarfism, and really I think its highly unlikely anyways.

So sorry to hear about your past experiences.

I know what you mean when you have things go not as planned with pregnancy.  I never got to enjoy any of mine, and though the complications were all different I always worried.  I would be really reassured knowing that your baby does not have other markers and that you have had multiple scans, I would think that the 1 measurement is a bit of a fluke, and is probably off a bit.  I have a short husband 5'7" and he was always in the 10th percentile growing up, he never really noticed he was short before dating me, I am 5'10"

Answer 2

My son's femur measurements were always quite a bit smaller than average also, and he was totally fine. I wouldn't worry too much. If there was a major issue the blood work would have shown some kind of increased risk. Is this the only scan you have had for growth? Were other scans off as well, or just this one?  

Answer 3

im sure if your docter was really worried about it he would of told u that the baby might have ds.any questions you have you should talk to with your docter.you have to make docters answer your questions because some docters are a pain in the *** to get information out off.

good luck

Answer 4

Do you have the exact measurements and the gestational ages when they were taken? I'm not a doctor, but a pathology assistant, and part of my job is to take bone measurements and compare then with normal values of developing fetuses and infants. If you would like, I'll be glad to look into this myself. Yes, a few millimeters one way or the other can make a big difference. I wouldn't worry too much though, as the percentile seems to be rising and the other values you stated seem within range.  

Answer 5

My son's femur also was consider small, the doctor made a big hoopla about it, he even suggested down syndrome and some friends even mentioned ending the pregnancy, I of course trusted in God's will, that was 14 years ago, my son is 13 and 6'2, perfectly healthy and normal, go figure!

Answer 6

Trust the other tests not the ultra sound.  It is hard to get an accurate measurement from an ultra sound.