Capurro calculator
The Capurro method estimates the newborn’s gestational age from physical examination findings. It is useful when obstetric dating (LMP or early ultrasound) is unavailable or unreliable. Score each feature below and the result appears in weeks and days.
For each feature, select the description that best matches the newborn. The somatic method uses 5 physical signs; the somatic-neurologic method adds 2 neurologic signs and drops nipple formation.
Sum of points + constant (204 for somatic, 200 for somatic-neurologic) = gestational age in days. Margin of error of about 1 week either way. Do not use alone in a severely ill or very preterm newborn; prefer obstetric dating (LMP/early ultrasound) when reliable.
Clinical decision-support tool for use by healthcare professionals. It does not replace clinical judgment or your unit's protocols.
How the calculation works
Add the points for the features assessed and add a constant: 204 for the somatic Capurro (5 signs: ear, breast tissue, nipple, skin texture and plantar creases) and 200 for the somatic-neurologic method (ear, breast tissue, skin, plantar creases, scarf sign and head position). The total is the gestational age in days; divided by 7, it gives weeks and days.
When to use each variant
The somatic method can be applied right after birth, including in a depressed newborn, because it does not depend on tone. The somatic-neurologic method requires a stable, awake newborn but tends to be more accurate. The method’s error is about one week either way, and it loses accuracy in extremely preterm infants.
Example
Newborn with the pinna partially incurved along the whole upper edge (16), breast tissue 0.5 to 1 cm (10), punctate nipple with a non-raised areolar edge (10), smooth skin with slight peeling (10) and creases on the anterior half of the sole (15). Sum: 61 points. 61 + 204 = 265 days, that is, 37 weeks and 6 days.
Frequently asked questions
Does Capurro replace gestational age by LMP or ultrasound?
No. Obstetric dating by a reliable LMP or first-trimester ultrasound is the reference. Capurro is an estimation method for when that information is missing or disagrees with the examination.
What is the difference between somatic and somatic-neurologic Capurro?
The somatic method uses five physical signs and the constant 204. The somatic-neurologic method swaps nipple formation for two neurologic signs, the scarf sign and head position, and uses the constant 200. The neurologic method requires a stable newborn.
Is Capurro valid for extremely preterm infants?
It loses accuracy below 29 weeks, because the minimum somatic score already corresponds to 29 weeks and 1 day. In those cases prefer the New Ballard score and obstetric dating.
References
- Capurro H, Konichezky S, Fonseca D, Caldeyro-Barcia R. A simplified method for diagnosis of gestational age in the newborn infant. J Pediatr. 1978;93(1):120-2.
- Brazilian Society of Pediatrics (SBP). Department of Neonatology. Assessment of gestational age in the newborn. Scientific document.
- Brazilian Ministry of Health. Newborn health care: a guide for health professionals. Volume 1. Brasília; 2014.
