Research review 191
Population-based cohort study
Short answer
Among 573 women in a Norwegian study, 25% had anaemia around 14 weeks after giving birth. The proportion with iron deficiency depended on how it was measured: 39% using ferritin, 19% using soluble transferrin receptor and 22% using estimated total body iron. The study highlights the importance of assessing postpartum iron status and explains why different tests yield different estimates.
What did the researchers investigate?
The researchers followed women from early pregnancy in STORK-Groruddalen, a population-based study conducted in Oslo in 2008 to 2010. At approximately 14 weeks postpartum, they measured haemoglobin, an oxygen-carrying component of blood, and three indicators of iron status. Anaemia was defined as haemoglobin below 12 g/dl. They also examined associations with dietary iron intake, iron deficiency in pregnancy, bleeding during childbirth and participants' backgrounds.
What did they find?
A quarter of the women had anaemia. Iron deficiency was identified in 39% using ferritin below 15 µg/L, 19% using elevated soluble transferrin receptor and 22% using estimated negative total body iron. Ferritin reflects iron stores. The other measures partly capture more advanced iron deficiency. Lower postpartum haemoglobin and poorer iron status were associated with insufficient dietary iron intake, anaemia or iron deficiency in pregnancy and postpartum haemorrhage. Differences were observed between participant groups. After adjustment for other factors, South Asian women had lower haemoglobin and higher soluble transferrin receptor levels.
How certain can we be?
The study used laboratory measurements in a defined population, but it was observational. It identifies associations rather than proving their causes. Estimates depend on test choice and thresholds. Samples were taken at one postpartum point, so they cannot describe recovery over several years. Data were collected in 2008 to 2010.
Who do the findings apply to?
573 participants from Groruddalen in Oslo who attended postpartum follow-up. The population included women from different backgrounds. The figures are not national prevalence estimates for everyone giving birth in Norway in 2026.
What might this mean in everyday life?
Severe or persistent fatigue after childbirth has several possible causes. Anaemia and iron deficiency are conditions clinicians may assess, especially after heavy bleeding or known iron deficiency during pregnancy. Symptoms and test results need to be interpreted together. Read about nutrition and health after childbirth.
What do we still need to know?
We need recent representative Norwegian measures of iron status throughout the postpartum period, information about access to testing, and studies following symptoms, functioning and treatment over time.
Sources
Original publication: Næss-Andresen M-L et al. Prevalence of postpartum anaemia and iron deficiency by serum ferritin, soluble transferrin receptor and total body iron, and associations with ethnicity and clinical factors: a Norwegian population-based cohort study. Journal of Nutritional Science. 2022;11:e46. DOI: 10.1017/jns.2022.45.
Related systematic review: Cochrane: treatment of postpartum iron-deficiency anaemia.
Original study published: 2022. Source checked: 9 November 2026.
This review is based on what the researchers themselves report about methods, results and limitations.