Fetal growth retardation: femurs, fontanels, and follow-up

Sixty-three term newborn infants with fetal growth retardation were evaluated within three days of birth. They were classified by length and head circumference. In group 1, both length and head circumference were less than the tenth percentile; in group 2, either length or head circumference was less than the tenth percentile; and in group 3, both length and head circumference were greater than the tenth percentile. Ponderal index (weight/length ratio), anterior fontanel size, and amount of epiphyseal ossification were also determined. Significantly lower birth weights and decreased ossification were found when groups 1 or 2 were compared separately with group 3. These differences were most marked when the weight/length ratio was less than 2.25. When the ponderal index was less than 2.0, epiphyseal ossification was usually absent (suggesting a chronic process). Epiphyseal ossification was positively correlated with birth weight and length but was unrelated to anterior fontanel size. Ossification was more often absent in males than females. There was a negative (inverse) correlation between birth weight and anterior fontanel size. Follow-up of 32 of these infants at age 1 year showed marked individual variations, but there were significant differences in incremental linear growth between groups 1 and 3, a finding which supports results of animal studies showing that catch-up growth may be related to skeletal immaturity. Physical measurements at birth in the individual baby with fetal growth retardation do not reliably predict subsequent growth.