A baby with Trisomy 13 or Trisomy 18 is not expected to gain weight and height as quickly as a healthy infant. Children with Trisomy 18 and Trisomy 13 are generally smaller at birth and grow more slowly than other children. 

Dr Bonnie Baty, Genetic Counselor at the University of Utah, created these growth curves in collaboration with SOFT (USA). These charts allow growth percentile comparison of infants and children with trisomy 18 and trisomy 13 with their peers. Unlike standardised growth charts, the SOFT (USA) charts are a combination of both male and female growth.

Source: Baty BJ, Blackburn BL, Carey JC. 1994. Natural history of trisomy 18 and trisomy 13: I. Growth, physical assessment, medical histories, survival and recurrence risk. Am J Med Genet 49: 175-188, © 1994 Wiley-Liss, Inc. 

We are grateful to Dr John Carey and Ann M Barnes for their permission to reproduce the weight, height and head circumference curves.