Question
Hello doctor,
My husband and I just went for a prenatal check-up and the results are as follows: 19 weeks and 2 days pregnant, fetal heart rate 146 beats/minute, biparietal diameter 43mm (45%), head circumference 157mm (15%), femur length 28mm (24%), abdominal circumference 125mm (14%), posterior placenta position group 2, maturity level 0. So I would like to ask the doctor if these parameters are good and please explain to me what the percentile index in the ultrasound result indicates? I sincerely thank you!
Chu Van Truong (1996)
Answer
Answered by Specialist level I Doctor Vo Ta Son - Doctor of Fetal Medicine - Center for Women's Health - Vinmec Times City International General Hospital.
Hello,
With the question "What does the percentile index in the ultrasound results indicate?", the doctor would like to answer as follows:
In statistical probability, the concept of percentile is to estimate the proportion of data in a data set falling into the higher or lower region for a given value. The doctor would like to give an example so that you can better understand the percentile index or %.
For example: the head circumference index is 157mm (15%), which means that this index of the baby corresponds to the 15th percentile of the gestational age of 19 weeks and 2 days. Normally, an index will be ranked from smallest to largest according to the percentile from 1 to 100. The indexes from the 10th - 90th percentile are normal. The standard average is the 50th percentile. If it is below the 10th percentile, it is called small (short), if it is above the 90th percentile, it is called large (long).
Therefore, in your ultrasound results, the fetal indexes are from the 14th - 45th percentile, which are also normal indexes, but below the average. You should supplement your diet and necessary vitamins. The 20-22 week morphological ultrasound milestone is very important for screening for fetal morphological abnormalities, so remember to have a thorough ultrasound at this milestone.
If you still have questions about the percentile index, you can go to a hospital in the Vinmec Health System for further examination and consultation. Thank you for your trust and for sending your question to Vinmec. Wish you good health.
Sincerely!
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