First trimester ferritin screening for pre-delivery anaemia as a patient blood management strategy.

Objectives: To determine the optimum approach and timing to screen for iron deficiency in pregnancy.

Background: There is a lack of consensus on identifying and treating iron deficiency during pregnancy. Patient blood management programs may be refined by evaluating outcomes.

Methods: Retrospective data collection on women delivering prior to and following implementation of patient blood management interventions. Ferritin, transferrin saturation and haemoglobin levels were evaluated in first and second trimesters as predictors of pre-delivery anaemia. The optimum time to screen was determined. Comparison with results following a quality improvement intervention was undertaken. A separate retrospective study was performed to validate the predictive value of ferritin using data extracted from the laboratory information system.

Results: Ferritin and transferrin saturation in first trimester detected women who subsequently had anaemia pre-delivery, with ferritin being most discriminatory. Both were superior to haemoglobin concentration. Iron studies in second trimester did not predict pre-delivery anaemia and haemoglobin remained poorly discriminatory. Iron studies lost predictive value when a systematic program ensured treatment of iron depletion during pregnancy. The ability of ferritin to predict pre-delivery anaemia in the first, but not the second, trimester was confirmed on the validation cohort.

Conclusion: First trimester serum ferritin may identify candidates for iron therapy during pregnancy. This strategy may be preferable to haemoglobin screening alone or universal replacement in centres at low risk of anaemia.