Pregnancy Ultrasound Report: BPD, HC, AC, FL, CRL and EFW Explained

Pregnancy ultrasound reports contain measurements, abbreviations and clinical conclusions. Understanding the labels can help you discuss the result, but the numbers need to be interpreted together with gestational age and the purpose of the scan. One measurement is not a complete assessment of a baby’s health.

Common pregnancy ultrasound abbreviations

ISUOG distinguishes fetal size at one examination from growth over time. Assessing growth requires measurements from examinations separated in time. The formula and reference chart also matter, so avoid comparing isolated numbers from unrelated online charts.

What does a percentile mean?

A percentile compares the measurement with a reference population at the same gestational age. ISUOG explains that an estimated weight at the 10th percentile means about 10 percent of fetuses in that reference group are smaller and 90 percent are larger. It does not mean that the baby is “only 10 percent developed.”

Small for gestational age and fetal growth restriction are related but different concepts. Some babies are small without the same risk as a baby whose growth is restricted. The obstetric team considers the measurements with Doppler findings and other clinical information before deciding what monitoring or management is needed.

AFI and DVP: amniotic-fluid measurements

AFI means amniotic fluid index and combines measurements from four areas. DVP means deepest vertical pocket and measures a selected pocket free of fetal parts and umbilical cord. They are different methods, so their values cannot be compared as if they were the same scale.

Low fluid is called oligohydramnios and increased fluid is called polyhydramnios. If either appears in the conclusion, ask what follow-up is needed. Do not use a single internet cutoff to decide whether a pregnancy is safe or whether treatment is required.

Questions to ask at your review

Ask whether the dating is established, whether the measurements are appropriate for that gestational age, whether growth can be compared with an earlier study and whether the fluid or Doppler assessment changes the plan. Bring earlier reports and record when the next appointment is due.

For healthcare professionals, an obstetric ultrasound machine should have the required probes, measurements and reporting workflow verified by the operator. See our equipment selection guide.

For related report questions, read about pregnancy Doppler blood-flow assessment, fetal wellbeing and BPP, and why measurements are not a fetal-sex code.

Sources

ISUOG: fetal biometry and growth guideline; ISUOG: fetal growth restriction; ISUOG: oligohydramnios; ISUOG: polyhydramnios. Reviewed 13 November 2026. General education; individual findings need clinical interpretation.