U.S. doctors online nowAsk doctors free
A 46-year-old member asked:

Can you really measure head and femur lenghts in ultrasound? what does that mean? i had an ultrasound done on my 26 week old baby and the doctor said the femur length measued 26 weeks, but the head an abdomen were 29 weeks. is this a sign of a deformity

2 doctor answers4 doctors weighed in
Dr. Geoffrey Rutledge
Internal Medicine 41 years experience
This : This finding probably does not represent a deformity or birth defect. Everyone is built a little differently and so are babies. The ultrasound technologist measures the baby's head circumference, head diameter, abdomen, and femur length (occasionally other measurements are also included). These measurements are compared to known averages in order to estimate a baby's age and make sure he/she is growing appropriately. However, averages also come with an acceptable range of variability. The dates that you have listed certainly could be within the normal range of variability, especially if no other abnormalities were identified during the ultrasound exam and your pregnancy has been progressing normally.
Dr. Boris Aronzon
Anesthesiology 24 years experience
Depends: Measurements are usually accurate. Discuss your concerns with your obstetrician. There are variations of normal.

90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more. Get help now:

Ask doctors free
Educational text
Free
Talk to a doctor
24/7 visits - just $39!
50% off with $15/month membership

90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more. Get help now:

Ask doctors free
Educational text
Free
Talk to a doctor
24/7 visits - just $39!
50% off with $15/month membership
Last updated Oct 3, 2016

Disclaimer:

Content on HealthTap (including answers) should not be used for medical advice, diagnosis, or treatment, and interactions on HealthTap do not create a doctor-patient relationship. Never disregard or delay professional medical advice in person because of anything on HealthTap. Call your doctor or 911 if you think you may have a medical emergency.