OBJECTIVES: Anaemia is a potential long-term sequel of obstetric blood loss, but the increased risk of anaemia in women who experience a haemorrhage compared to those who do not has not been quantified. We sought to quantify this risk and explore the duration of increased risk for these women. METHODS: Systematic review of articles published between 1990 and 2009. Data were analysed by high- and low-income country groupings. Prevalence and incidence ratios, and mean haemoglobin levels were compared. RESULTS: Eleven of 822 studies screened were included in the analysis. Most studies showed a higher prevalence or incidence of anaemia in women who had experienced haemorrhage than in those who did not, irrespective of the timing of measurement post-partum. In high-income countries, women who had a haemorrhage were at 5.68 (95% CI 5.04-6.40) times higher risk of post-partum anaemia than women who did not. In low-income countries, the prevalence of anaemia was 1.58 (95% CI 0.96-2.60) times higher in women who had a haemorrhage than in women who did not, although this ratio was greater when the study including mild anaemia in its definition of anaemia was excluded (1.93, 95% CI 1.42-2.62). Population-attributable fractions ranged from 14.9% to 39.6%. Several methodological issues, such as definitions, exclusion criteria and timing of measurements, hindered the comparability of study results. CONCLUSIONS: Women who experience haemorrhage appear to be at increased risk of anaemia for many months after delivery. This important finding could have serious implications for their health care and management.