title: Pregnancy-specific reference ranges for haematological variables in a Scottish population.
abstract: Using laboratory reference ranges, B₁₂ deficiency is inappropriately diagnosed and treated in pregnancy. We aim to define reference ranges for ferritin, folate, haemoglobin and B₁₂ in a pregnant population with advancing gestation. A total of 190 women participated in a cross-sectional study, 113 in the 1st and 77 in the 3rd trimester. All variables studied except red cell folate, decreased significantly from the 1st to the 3rd trimester. A total of 34% (64/190) of women were found to have 'low' B₁₂ as defined by traditional ranges. In women with anaemia and apparent B₁₂ deficiency, co-existing ferritin deficiency was demonstrated. All women with 'low' B₁₂ levels were invited to attend postnatally for re-testing. A total of 28% (18/64) attended, in whom all B₁₂ levels spontaneously increased. The use of gestation specific reference ranges for haematological variables may reduce inappropriate diagnosis of B₁₂ deficiency. In most women with apparent low B₁₂ levels and anaemia, ferritin deficiency was demonstrated. Therefore iron should be the initial management therapy.
authors.affiliation: Obstetrics and Gynaecology, Worcestershire Royal Hospital, Worcester, UK. rgane@doctors.org.uk
authors.forename: R C
authors.initials: RC
authors.lastname: Shields
authors.forename: V
authors.initials: V
authors.lastname: Caric
authors.forename: M
authors.initials: M
authors.lastname: Hair
authors.forename: O
authors.initials: O
authors.lastname: Jones
authors.forename: L
authors.initials: L
authors.lastname: Wark
authors.forename: M D
authors.initials: MD
authors.lastname: McColl
authors.forename: J E
authors.initials: JE
authors.lastname: Ramsay
mesh_terms: D000293:Adolescent; D000328:Adult; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D005293:Ferritins / Q000097:blood*; D005492:Folic Acid / Q000097:blood*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D011247:Pregnancy / Q000097:blood*; D011261:Pregnancy Trimester, First / Q000097:blood; D011263:Pregnancy Trimester, Third / Q000097:blood; D012016:Reference Values; D012606:Scotland; D014805:Vitamin B 12 / Q000097:blood*; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D005293:Ferritins; D005492:Folic Acid; D014805:Vitamin B 12