Incidence and predictors of iron deficiency anaemia in parturients undergoing elective caesarean section at a tertiary hospital in New Zealand: a retrospective, observational cohort study

Abstract

Background: Worldwide, iron deficiency anaemia in pregnancy is a significant problem which can be especially problematic when delivery is by caesarean section, a procedure associated with significant blood loss. Optimising iron stores pre-delivery remains an overarching goal. We aim to measure the incidence of iron deficiency anaemia in patients undergoing elective caesarean section at our institution and determine any associated predictors, as well as adverse outcomes. Methods: A retrospective, observational cohort study of patients presenting for elective caesarean section over a two-year period. Patient data was collected from hospital electronic records. Iron deficiency anaemia was defined a haemoglobin < 110 g/L and a ferritin < 30 μg/L in the three-month period prior to delivery. The primary aim was to establish the incidence of iron deficiency anaemia at the time of delivery and any associated predictors. Secondary outcomes included any association between the primary outcome and complications defined by the hospital discharge complication coding system, as well as an evaluation of the number of blood tests carried out antenatally per trimester. Results: One thousand and ninety-three women underwent caesarean section over the study period and 16.2% had iron deficiency anaemia. Patients with iron deficiency anaemia were more likely to be of Māori and Pacific Island ethnicity, have a greater booking body mass index, be younger and have a greater parity. Pre-operative anaemia was associated with a greater likelihood of post-operative blood transfusion. Conclusions: There remains potential for optimisation of iron deficiency anaemia in our local population undergoing elective caesarean section.