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Dr Pixel 2.0Women's imaging diagnosis

PLATFORM FOR EDUCATION AND DECISION SUPPORT IN WOMEN'S IMAGING

Avaliação do Crescimento Fetal (INTERGROWTH-21st)

Como funciona esta calculadora

Informe o peso fetal estimado em gramas (g).

Faixa válida

  • • Medida: 100–6000 g
  • • Idade gestacional: 22–40 semanas

Idade gestacional *

Understand the method

How the percentile assessment works (INTERGROWTH-21st)

This tool allows objective, standardised assessment of fetal growth by comparing biometric measurements from ultrasound with expected values for gestational age, based on the international INTERGROWTH-21st standards (International Growth Standards for the 21st Century). It covers head circumference, biparietal diameter, occipitofrontal diameter, abdominal circumference, femur length, and estimated fetal weight.

Estimated fetal weight percentile (INTERGROWTH-21st)

Fetal growth classification by percentile

P3P10P90P97
FGR< P3
SGAP3–P10
AGAP10–P90
LGAP90–P97
Macrosomia≥ P97

Z-score and percentile

The calculation provides Z-score and percentile, helping identify whether fetal growth is adequate, restricted, or accelerated. Automatic classification (FGR, SGA, AGA, LGA, Macrosomia) is applied to AC and estimated fetal weight, as both are directly related to fetal weight.

Definitions used

FGR — Fetal Growth Restriction
Pathological condition characterised by the fetus failing to reach its growth potential, usually associated with placental insufficiency. Not defined by weight alone.
SGA — Small for Gestational Age
Estimated fetal weight below the 10th percentile for gestational age, which may represent constitutionally small fetuses or FGR cases.
AGA — Adequate for Gestational Age
Estimated fetal weight between the 10th and 90th percentiles for gestational age.
LGA — Large for Gestational Age
Estimated fetal weight above the 90th percentile for gestational age.
Fetal macrosomia
Extreme form of excessive growth, generally defined as estimated fetal weight ≥ 97th percentile or elevated absolute weight (often ≥ 4,000 g), with special clinical relevance in diabetic pregnancies.

Correct interpretation depends on well-defined gestational age and biometric measurements obtained with adequate technique. Definitive diagnosis of fetal growth restriction requires clinical and fetal Doppler correlation — isolated percentile does not define diagnosis.

Common questions

Frequently asked questions about fetal percentiles

What is INTERGROWTH-21st?+
INTERGROWTH-21st stands for International Growth Standards for the 21st Century, an international project that established modern, global standards for fetal and neonatal growth, used in this calculator for Z-score and percentile.
Which biometric measurements does this calculator assess?+
Head circumference (HC), biparietal diameter (BPD), occipitofrontal diameter (OFD), abdominal circumference (AC), femur length (FL), and estimated fetal weight (EFW).
Which measurements does the automatic classification (FGR, SGA, AGA, LGA, Macrosomia) apply to?+
Automatic fetal growth classification by percentile is applied to AC (abdominal circumference) and to estimated fetal weight, as both are directly related to fetal weight.
Does an isolated percentile define a fetal growth restriction diagnosis?+
No. Definitive diagnosis of fetal growth restriction requires clinical and fetal Doppler correlation — isolated percentile does not define diagnosis.