Estimation of fetal age is an important component of prenatal evaluation. The measure of the Crown-Rump Length (CRL) by ultrasound is one of the most frequently used methods to determine it. However, in certain pathologies, this measure could lose accuracy, and other measures should be taken to evaluate fetal age and to determine the normal growth of the conceptus. The main objective of this research was to compare different morphometric parameters with CRL in normal human fetuses to determine which of them has a stronger correlation with gestational age to be a useful measure when CRL could not be appropriately evaluated. We measured 10 different morphometric parameters and the weight in 120 human fetuses product of abortion that had externally normal morphology, and a Pearson´s Correlation test was made with each of the parameters with the gestational age determined using the CRL.
Each of the 10 parameters had a significantly strong correlation with CRL. However, some of them have a stronger correlation and should be preferred when CRL is not available. If available, fetal age should be estimated using an ultrasound technique and measuring the CRL. Nevertheless, if an alteration in one of the structures affects its measure, a different parameter should be used. The limitations of each parameter should be noticed before using them.