Background: Microcephaly (MiC) is defined as head circumference (HC) dimensions smaller than the normal standards.
Objective: To detect MiC with a mathematical formula.
Materials and methods: The 0 to 5 years head HC percentile data for girls and boys reported by the World Health Organization were used. To assess early childhood, these growth standards are available on its website for international use. Mathematical formulas best estimating the 3rd percentile curves were defined using basic regression analysis methods.
Results: The mathematical models obtained as a result of logarithmic regression analysis with the highest coefficient of determination values (R2 = 0.991 for girls; R2 = 0.991 for boys) were identified as the best model. The formulas of HC = 34.025 + 3.283 ∗ ln (age as months), and HC = 35.475 + 3.14 ∗ ln (age as months) were determined for girls and boys, respectively. A limitation of these formulas is that they do not provide the HC at birth (ln (0) = undetermined).
Conclusion: Microcephaly can be estimated using the mathematical formulas with a calculator without using percentile scales, mobile applications, software, or the Internet.
Copyright © 2021 by Mutaz B. Habal, MD.