Intergenerational influences affecting birth outcome. I. Birthweight for gestational age in the children of the 1958 British birth cohort

There is considerable literature on intergenerational influences on birthweight. Few studies have been able to investigate such influences on the more basic measures of birthweight for gestational age and gestational age itself. This paper considers fetal growth. The investigations are derived from the 1958 British birth cohort followed from birth to age 33 years. Included were questions on physical and social characteristics of each parent and the grandparents, and birth details of parent and first child. Ln the present study, fetal growth in non-preterm babies, after adjustment for the known effects of smoking and sex of the child, is explained best by factors relating to the parent's own growth, primarily in utero, but also to adulthood. There are small additional effects of education or social class but not of parent's gestational age. Only 15% of the variability in the child's fetal growth can be explained by the mother's characteristics and approximate to 7% by the father's. Parent's own fetal growth accounts for nearly half of the variability if unadjusted for other factors and nearly a third after adjustment for sex of child, smoking, parental height and weight, maternal age at menarche and paternal age at first birth. Parental fetal growth makes the greatest anthropometric contribution.