Background Anaemia during pregnancy is common and increases the risk of adverse perinatal outcomes. Epidemiologic research on anaemia during pregnancy largely relies on International Classification of Diseases, Clinical Modification, 10th Revision (ICD-10) diagnosis codes, despite limited evidence on their validity. Objective Our objective was to assess the validity of ICD-10 codes against haemoglobin and haematocrit values in identifying anaemia during pregnancy.
