What Are Percentiles In Obstetric Ultrasound? | Fetal Biometric Parameters (FL, BPD, HC, AC) USG

Percentile means where the fetus’ size is compared to others. For example, if a fetus’ measurement is in the 50th percentile, it means the fetus is right in the middle—bigger than 50% of babies but smaller than the other 50%.
If a baby is in the 10th percentile, they are smaller than 90% of other babies, and only 10% are smaller than them.
If a baby is in the 90th percentile, they are bigger than 90% of other babies, and only 10% are larger.
10th to 90th Percentile: This range is generally considered normal. A fetus within this range is growing well and is usually considered healthy in terms of size for its gestational age.
Below the 10th Percentile: This can indicate fetal growth restriction (FGR) or small for gestational age (SGA). Babies in this range may be smaller than expected, which can be a sign of potential problems with growth or nutrition in the womb. Doctors may monitor these babies more closely to ensure they are healthy.
Above the 90th Percentile: This suggests the fetus is large for gestational age (LGA), which could indicate conditions like macrosomia (excessive fetal weight). Fetus larger than the 90th percentile might be linked to factors like gestational diabetes, and doctors may pay closer attention to how the pregnancy progresses.

Summary:
Normal: 10th to 90th percentile.
Abnormal:
Below 10th percentile – Possible growth restriction (small for gestational age).
Above 90th percentile – Possible macrosomia (large for gestational age).