[The fetal development curves of newborn infants in the Hospital de Cruces (Vizcaya). II. Length, head circumference and ponderal index].

Taking a 27,641 live birth sample, without congenital or genetical malformations and from single pregnancies, delivered at Cruces Hospital (Vizcaya) from February 17 1987 to December 31st 1992, fetal growth curves of length, head circumference and ponderal index, have been developed. For every variable and in every gestational week, percentile distribution, mean and standard deviation and 95% confidence interval of the mean have been calculated. Charts of intrauterine growth in length, head circumference and weight-length ratio must be use in conjunction with intrauterine weight charts allowing the identification of infants with unusual prenatal growth patterns.