Pregnancy-specific reference ranges for haematological variables in a Scottish population

• Published in: Journal of obstetrics and gynaecology Vol. 31; no. 4; pp. 286 - 289
• Main Authors: Shields, R. C., Caric, V., Hair, M., Jones, O., Wark, L., McColl, M. D., Ramsay, J. E.
• Format: Journal Article
• Language: English
• Published: England Informa Healthcare 01-05-2011; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Adolescent; Adult; Erythrocytes - metabolism; Female; Ferritin; Ferritins - blood; folate; Folic Acid - blood; haemoglobin; Hematology; Hemoglobins - metabolism; Humans; Obstetrics; Pregnancy; Pregnancy - blood; Pregnancy Trimester, First - blood; Pregnancy Trimester, Third - blood; reference range; Reference Values; Scotland; Vitamin B; Vitamin B 12 - blood; Vitamin deficiency; Womens health; Young Adult; Scotland
• ISSN: 0144-3615; 1364-6893
• DOI: 10.3109/01443615.2010.545900

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.