Equations to estimate fetal age at the moment of death in the Mexican population

Metric standards are presented for the estimation of fetal age at the time of death in the Mexican population. To obtain these standards, both metric and radiological studies were conducted on 97 fetuses and complete stillborn infants of both sexes, phenotypically normal between 10 and 38 weeks of morphological age. All the fetuses used were the product of spontaneous abortions in Mexico City between 1990 and 2000. Equations were obtained by calibrating quadratic linear regression models adjusted for the diaphyseal length of the humerus, radius, ulna, femur, tibia and fibula, characterized as the most adequate indicators to represent the growth of long bones in this age group, and verified by the evaluation of the model assumptions and the coefficient of determination (R2). To conclude, these models facilitate a more precise prediction in fetuses of the Mexican population, constituting the first metric standards of their type at a national level.