Variation in antenatal anaemia guidelines across the NHS in the United Kingdom: A cross-sectional study.

Antenatal anaemia affects up to 30% of pregnant women in the United Kingdom and is a recognised clinical priority. National management guidance is published by the British Society of Haematology (BSH), but the extent to which local National Health Service (NHS) guidelines align with it is unknown. We conducted a cross-sectional document analysis of antenatal anaemia guidelines from 49 NHS sites across the United Kingdom, obtained through two national research programmes. Two reviewers independently extracted data on screening, diagnosis, treatment and monitoring, using the 2020 BSH guideline as the national reference standard. The included guidelines represented approximately 33% of annual UK births. Screening and diagnostic haemoglobin thresholds were broadly consistent with BSH guidance, whereas substantial variation was concentrated in treatment and monitoring: oral iron indications, dosing and duration; haemoglobin thresholds and clinical criteria for intravenous iron; and the timing, biomarkers and response definitions used after treatment. Ferritin thresholds, reassessment intervals and response criteria were frequently absent or divergent. Variation was greatest in domains where the underlying evidence base is least resolved. These findings characterise the nature and extent of guideline-level variation across NHS maternity care and identify priority areas for future research and national guideline development.