Preterm and small-for-gestational-age birth across generations

OBJECTIVE: Our purpose was to determine whether women who were themselves small for gestational age at birth are at risk of giving birth to a small-for-gestational-age child and whether women who were themselves preterm at birth are at risk for preterm delivery. STUDY DESIGN: Women born in Copenhagen as subjects in the Danish Perinatal Study (1959 to 1961) were traced through the Danish Population Register. Information was obtained on their pregnancies during 1974 through 1989. RESULTS: A total of 25% of the children of small-for-gestational-age women were small for gestational age compared with 11% of the children of non-small-for-gestational-age women. Eleven percent of the children of preterm women were preterm compared with 7% of the children of women born at term. The adjusted odds ratios were 2.0 (95% confidence interval 1.4 to 3.0) for women who were small for gestational age to have small-for-gestational-age children and 1.5 (95% confidence interval 0.9 to 2.5) for women who were born preterm to have preterm children. Small-for-gestational-age women were not at significantly increased risk of preterm delivery (odds ratio 1.2), and preterm women were not at significantly increased risk of having small-for-gestational-age children (odds ratio 1.3). CONCLUSIONS: Reduced intrauterine growth of the mother is a risk factor for reduced intrauterine growth of her children. However, preterm birth of the mother is not strongly associated with preterm birth of her children.