Forgotten Diseases Research Foundation


Size at Birth by Gestational Age

We constructed curves for size by gestational age from a study that collected data from all singleton deliveries during the years 1993-2000 in Chile (1). According to the study, 2,049,446 children were born during that period. The study authors created data for the curves by removing statistical outliers (children who were improbably large or small) from the analysis. Percentile curves for length and weight at birth were constructed from the data for both the sexes. Unfortunately, the authors mixed data for both sexes. The curves provide information for gestational ages 22 to 42 weeks, using smoothed data points for the 2nd to the 90th percentiles.

We also made the head circumference curves for singleton newborns from a study of 82,604 neonates (2). The study authors excluded infants whose mothers suffered from a variety of medical conditions that affect fetal growth, including diabetes, pregnancy-induced hypertension, and RH incompatibility. Infants whose gestational ages were not precisely known and those with major congenital malformations were also excluded. The curves give data for values of 10th-50th-90th percentiles and goes from 31 to 42 weeks gestation.

Head Circumference

Velo-Cardio-Facial Syndrome (Chromosome 22q11 Microdeletion Syndrome)

Velo-cardio-facial syndrome (VCFS) is also known as Di George syndrome, chromosome 22q11 deletion syndrome and Del22q11 syndrome, among other names. VCFS varies from person to person, but overall, it is characterized by congenital heart defects, kidney problems, an abnormal palate, and problems with the immune system, including susceptibility to infection. Patients may also have learning difficulties and a characteristic appearance. Short stature is also common.

A study of growth in Chilean children with VCFS is freely available online (3). Data was collected from 239 individuals, or ~68% of known VCFS patients in Chile at the time of the study. Sex-specific growth curves for ages 0-24 months were constructed with 10th, 50th and 90th percentiles. Figures 1-4 in the paper are curves for weight and length in girls and boys aged from 0 to 24 months.


  1. 1. González RP et al. (2004) A national birth weight distribution curve according to gestational age in Chile from 1993 to 2000. (In Spanish) Rev Med Chile 132(10):1155-1165. Full text from Scielo.
  2. 2. Alarcon JR et al. (2008) Anthropometric growth in chilean newborns. (In Spanish) Rev Chil Pediatr 79(4): 364-372. Full text from Scielo.
  3. 3. Guzman ML et al. (2012) Growth in Chilean infants with Chromosome 22q11 Microdeletion Syndrome. Am J Med Genet Part A 158A:2682-2686. Abstract on PubMed.     Full text from publisher.

Page last modified on 18 April 2022.