BACKGROUND: Teenage motherhood is relatively common in the UK, but little is known about related health inequalities in this population. We estimated cause-specific mortality risks over three decades in a nationally representative cohort. METHOD: We examined premature mortality in a 1.1% sample of all women who were teenagers in England and Wales during the 1970s, 1980s and 1990s using data from the Office for National Statistics Longitudinal Study (ONS LS). Our primary outcome was suicide. Long-term follow-up to 31 December 2006, to a potential maximum age of 49 years, was achieved through near-complete routine linkage to national mortality records. We created a time-dependent exposure variable, with relative risks estimated according to age when women first experienced motherhood versus a reference group of those currently without children. RESULTS: Women who were teenage mothers were around 30% more likely to die prematurely by any cause and almost 60% more likely to die unnaturally, whereas first-time motherhood at mature age conferred lower risk compared to women without children. Teenage motherhood was associated with a more than doubled risk of suicide [mortality rate ratio (MRR) 2.23, 95% confidence interval (CI) 1.30-3.83], and elevated risks of fatal cancer of the cervix and lung were also found. Changing the reference category to first-time mothers at 20 years and above also revealed a significant elevation in risk of accidental death. CONCLUSIONS: The complex psychosocial needs of these women require greater attention from clinicians, public health professionals, social services and policymakers. Their elevated risk of poor health outcomes may persist well beyond the actual teenage motherhood years.