There is considerable interest in the mechanisms maintaining early reproduction in the most socioeconomically disadvantaged groups in developed countries. Previous research has suggested that differential exposure to early-life factors such as low birthweight and lack of paternal involvement during childhood may be relevant. Here, we used longitudinal data on the female cohort members from the UK National Child Development Study (n = 3,014-4,482 depending upon variables analyzed) to investigate predictors of early reproduction. Our main outcome measures were having a child by age 20, and stating at age 16 an intended age of reproduction of 20 years or lower. Low paternal involvement during childhood was associated with increased likelihood of early reproduction (O.R. 1.79-2.25) and increased likelihood of early intended reproduction (O.R. 1.38-2.50). Low birthweight for gestational age also increased the odds of early reproduction (O.R. for each additional s.d. 0.88) and early intended reproduction (O.R. for each additional s.d. 0.81). Intended early reproduction strongly predicted actual early reproduction (O.R. 5.39, 95% CI 3.71-7.83). The results suggest that early-life factors such as low birthweight for gestational age, and low paternal involvement during childhood, may affect women's reproductive development, leading to earlier target and achieved ages for reproduction. Differential exposure to these factors may be part of the reason that early fertility persists in socioeconomically disadvantaged groups. We discuss our results with respect to the kinds of interventions likely to affect the rate of teen pregnancy.
(c) 2009 Wiley-Liss, Inc.