Prevalence of maternal anaemia and its predictors: a multi-centre study.

OBJECTIVE: To investigate the prevalence, predictors, and management of anaemia in pregnancy. STUDY DESIGN: A multi centre study across 11 maternity units in the UK. Data were collected over a two week study period in 2008 on maternal history, haemoglobin (Hb) and ferritin concentrations, iron therapy during pregnancy and in the postpartum period. Logistic regression models were used to explore factors associated with anaemia during pregnancy. Main outcomes included anaemia, defined as Hb<11 g/dl at booking, Hb<10.5 g/dl in subsequent antenatal visits, and Hb<10 g/dl postnatally. RESULTS: Completed data were received on 2103 of 2155 women (97% completion rate). Of these, 24.4% (502) (95% CI 22.5-26.2%) were anaemic at some stage during the antenatal period. Predictors for having anaemia by 32 weeks gestation included young maternal age (odds ratio 1.96, 95% CI 1.38-2.79), non-white ethnic origin (odds ratios varied 1.37-2.89 depending on ethnic origin) and increasing parity (odds ratio 1.24, 95% CI 1.08-1.41). Of women who had postnatal Hb levels checked, 30% (309/1031) were anaemic and, depending on centre, 16% to 86% of these received iron therapy. CONCLUSION: Anaemia was reported in nearly one in four women in the antenatal period, and nearly one in three of the women who had a postpartum Hb checked. Despite national guidelines, there was considerable variation in administration of iron including low utilisation of parenteral iron therapy. Future research needs to focus on the consequences of iron deficiency anaemia for maternal and infant health outcomes and effectiveness of implementation strategies to reduce anaemia.