Querying the value of indiscriminate iron supplementation in pre-eclampsia: a cross-sectional study

Objective: To determine the prevalence and type of anaemia and its association with pre-eclampsia (PE) in pregnant South Africans of African ancestry. Design Cross-sectional study design Setting A regional hospital in KwaZulu-Natal, South Africa. Sample 671 women seeking antenatal care. Methods Participants had haemoglobin(Hb), anthropometric measurements, HIV status, blood pressure levels(BP) and proteinuria measured to determine PE. Iron studies and transferrin receptor levels were assessed in a subset and chi-square tests of association between normotensive and pre-eclampsia sub-groups and blood parameters were conducted. Results No difference in Hb concentration amongst the 4 groups (F (3,621)=0.981, p< .001, η2=.014) was observed. A chi-square test of association (χ2(3)=6.674, p=.083) showed no associations between study groups and having anaemia. The severity of anaemia did not vary amongst study groups (χ2(12) =10.756, p=.550). Using ferritin, there was an association between the study groups having an iron deficiency, anaemia, both or neither (χ2(3)=12.559, p=.045) with a positive association between normotensive term and iron deficiency (adjusted residual(AR) 2.2) and positive association between early-onset PE(AR 2.4). Similar trends were found for transferrin and soluble transferrin receptor ferritin index. Twenty-two percent of the participants were not iron deficient. Conclusion Early-onset PE is associated with high iron status and not anaemia. Normotensive term pregnancies were associated with iron deficiency anaemia. Broad iron supplementation without adequate determination of iron deficiency in pregnant women needs to be revisited. Funding National Research Foundation (TTK170508230162), University of KwaZulu-Natal UCPD and Medical Research Council of South Africa(SIR Grant UNS14197). Keywords Anaemia, iron deficiency, pre-eclampsia