Impact of adolescent age on maternal and neonatal outcomes in the Born in Bradford cohort

OBJECTIVES: Explore associations between maternal and neonatal outcomes and maternal age, with particular reference to adolescent women. DESIGN: Population-based cohort study. SETTING: Maternity department of a large hospital in Northern England. PARTICIPANTS: Primiparous women delivering a singleton at Bradford Royal Infirmary between March 2007 and December 2010 aged ≤19 years (n=640) or 20–34 years (n=3951). Subgroup analysis was performed using women aged ≤16 years (n=68). Women aged 20–34 years were used as the reference group. PRIMARY OUTCOME MEASURES: Maternal and neonatal outcomes. RESULTS: The odds of extremely low birth weight (<1000 g) were significantly higher in the adolescent group (≤19 years) compared with the reference group (adjusted OR (aOR) 4.13, 95% CI 1.41 to 12.11). The odds of very (<32 weeks) and extremely (<28 weeks) preterm delivery were also higher in the adolescent group (aOR 2.12, 95% CI 1.06 to 4.25 and aOR 5.06, 95% CI 1.23 to 20.78, respectively). Women in the adolescent group had lower odds of gestational diabetes (aOR 0.35, 95% CI 0.20 to 0.62), caesarean delivery (aOR 0.53, 95% CI 0.42 to 0.67 and instrumental delivery (aOR 0.53, 95% CI 0.41 to 0.67). CONCLUSIONS: This study identifies important differences in maternal and neonatal outcomes between women by age group. These findings could help in identifying at-risk groups for additional support and tailored interventions to minimise the risk of adverse outcomes for these vulnerable groups. Further work is needed to identify the causal mechanisms linking age with outcomes in adolescent women where significant gaps in the literature exist.