Tell me about a "short femur"

[cc1003]

My younger sister (19) got her 26 week u/s today and the results were that the baby had a "short femur". It is measuring two weeks behind.

I've googled this and a million different things come up, one of which is down's.

Do you have any personal experience information that I could have?

[Sputterduck]

I have no idea.

I hope the baby just has short legs. My son wears a 4t up top and a 2t down below. It's a Korean thing I guess. His father is the same exact way.

[joshsmom]

Just one short femur or both (long bones)? Both my kids measured short femurs, generally 2-5 weeks behind depending on the US. We (myself and both of them) have a genetic growth disorder called hypochondroplasia. It is a very "mild" form of dwarfism.

Shortened long bones can be an early, (not always accurate), indicator of several forms of dwarfism.

[cc1003]

Bump

[leosmommy]

Could it be that her dates are just off, or do the rest of the babies measurments come back normal?

[HIJKMommy]

It is one of the #1 signs of Down's Syndrome. AS an ultrasound technologist it is the very first thing we look for when a genetic test comes back positive, but by no means does it mean that it is Down's Syndrome. Did your sister have the AFP test or any other genetic testing?

[CatEyes]

I came acrossed this while googling "short femur". A lady has the same problem as your sister and she posted and got an answer from a an OB. Here is a link
http://secure.caregroup.org/obgyn/ask_doc/ask_doc_questDisplay.asp?id=81
And the artlicle is below.
Also here is a google search i did and found different links about "short femur" that you might want to check out to.
http://www.google.com/search?hl=en&client=opera&rls=en&hs=HgJ&q=short+femur&btnG=Search
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ASK THE DOCTOR
Pregnancy/Postpartum
I am 38 years old and pregnant. I had an ultrasound during week 20 and was told that my baby has a short femur and that this may be a sign of Down syndrome. Is this true? What should I do?

OB's response
The femur (thigh bone) is the longest bone in the body and is measured as part of a second trimester ultrasound as part of the evaluation for birth defects. There has been much speculation about whether short femur length is a predictor for Down syndrome - trisomy 21 - a chromosome abnormality that causes mental retardation and some associated physical defects. However, the data linking short femur to Down syndrome differ significantly among research studies. Some studies indicate that short femur is four times more common among babies born with Down syndrome. Other research has shown that short femur, alone, may not be more common among fetuses with Down syndrome than in normal fetuses.

The variation among studies may be attributed to differences in the quality of ultrasound equipment, differences in technique and expertise of sonographers, differences in gestational ages of pregnancies studied, disagreement about the definition of short femur, and racial variability.

Femur length is just one of a number of ultrasound findings that are referred to as soft markers. Soft markers are abnormal findings that may increase the risk of a fetus having a chromosome abnormality, but do not represent structural abnormalities.

Ultrasound studies have demonstrated that major chromosomal defects are usually associated with multiple soft markers. Most studies have found that a combination of two or more abnormal findings substantially increases the risk for Down syndrome. Therefore, it is recommended that when one soft marker is detected during a routine ultrasound examination, a thorough check be made for other associated markers and abnormalities.

In your particular case, the good news is that only one soft marker was found. However, the other variable to factor into this equation is your age. The likelihood that a reproductive cell will contain an extra copy of chromosome 21 increases dramatically as a woman ages. An older mother is more likely than a younger mother to have a baby with Down syndrome. The likelihood that a pregnant woman under the age of 30 will have a baby with Down syndrome is less than 1 in 1,000. At your age of 38, the risk of Down syndrome is about 1/115.

If your ultrasound was performed by a practitioner with special expertise (perinatologist or radiologist), and your baby was found to have a short femur and all other measurements were normal, she is likely to have normal chromosomes. However, given that you are reaching an age where your risk for carrying a baby with Down syndrome is increased, and a soft marker has been identified— even if a controversial one and found in isolation— I would recommend genetic counseling.

Remember, screening tests, such as ultrasound, can't provide an absolute diagnosis. It is important to keep in mind that even the best combination of ultrasound findings and other variables is only predictive and not diagnostic. For true diagnosis, the chromosomes of the baby must be examined, typically by amniocentesis.

Amniocentesis is a diagnostic procedure performed by inserting a hollow needle through the abdominal wall into the uterus and withdrawing a small amount of fluid from the sac surrounding the fetus. According to the Centers for Disease Control and Prevention (CDC), the risk of miscarriage due to amniocentesis is between 1 in 200 and 1 in 400, depending on the skill and experience of the doctor performing it. There is also a very slight risk of uterine infection in the days following the procedure (less than one in 1,000), which can sometimes lead to miscarriage. These are all things you should discuss with your partner, your practitioner, and a genetic counselor.