This calculator is to be retired This page keeps the older Biometry 3.1 calculations available in a mobile-friendly layout while the newer Biometry 5 workflow is being restored and validated.

Fetal Biometry Calculator 3.1

Enter gestational age and the measured value. Then select the appropriate biometric, growth, or Doppler calculation.

Measured value should be entered as millimeters, grams, or ratio, depending on the selected calculation.

Biometry 5: Main EFW Head Jeanty HC Skeletal Doppler

Gestational age weeks

Days

Measured value (mm, g, or ratio)

Results

HeadBPD, HC, Jeanty HC, TCD, mandible

Chest, abdomen, and kidneysThorax, AC, colon, renal measurements

ExtremitiesLong bones and foot length

Growth / DopplerEFW, uterine artery, umbilical artery, MCA PI

Threshold values and clinical flags

Finding	Clinical note
DVP < 2 cm	Oligohydramnios in singleton or twin pregnancy.
DVP ≥ 8 cm	Polyhydramnios in singleton or twin pregnancy. Mild 8–11 cm, moderate 12–15 cm, severe ≥16 cm.
AFI ≥ 24 cm	Polyhydramnios in singleton pregnancy. Mild 24.0–29.9 cm, moderate 30.0–34.9 cm, severe ≥35 cm.
MCA PSV ≥ 1.5 MoM	Increased likelihood of fetal anemia.
CPR less than 1.08	Increased risk for adverse perinatal outcome in a growth-restricted fetus; interpret with gestational age and local Doppler reference standards.
FL/AC ratio < 0.16	Raises concern for lethality in suspected skeletal dysplasia.
Inferior facial angle less than 49°	Increased likelihood of micrognathia.
Jaw index less than 23	Supports diagnosis of fetal micrognathia.
Fetal HC ≥ 3 SD below mean	Concern for fetal microcephaly.
Fetal HC ≥ 5 SD below mean	Pathologic microcephaly considered highly likely.
Lateral ventricle atrial diameter ≥ 10 mm	Ventriculomegaly: mild 10–12 mm, moderate 13–15 mm, severe >15 mm.

Selected references from legacy calculator

Hadlock FP, et al. Estimating fetal age: computer-assisted analysis of multiple fetal growth parameters. Radiology. 1984;152:497-501. PMID: 6739822.
Hadlock FP, et al. In utero analysis of fetal growth: a sonographic weight standard. Radiology. 1991;181:129-133. PMID: 1887021.
Chitty LS, et al. Charts of fetal size: head measurements. Br J Obstet Gynaecol. 1994;101:35-43. PMID: 8297866.
Chitty LS, et al. Charts of fetal size: abdominal measurements. Br J Obstet Gynaecol. 1994;101:125-131. PMID: 8305386.
Chitty LS, Altman DG. Charts of fetal size: limb bones. BJOG. 2002;109:919-929. PMID: 12197373.
Mari G, et al. Noninvasive diagnosis by Doppler ultrasonography of fetal anemia due to maternal red-cell alloimmunization. N Engl J Med. 2000;342:9-14. PMID: 10620643.

All calculations should be confirmed before clinical use and interpreted in context.