The effect of individualized iron supplementation on iron status in Dutch preterm infants born between 32 and 35 weeks of gestational age: evaluation of a local guideline

Objective: Iron deficiency (ID) and iron deficiency anemia (IDA) in early life are associated with adverse effects. Preterm infants are at risk for developing ID(A). Considering that not every preterm infant develops ID(A) and the potential risk of iron overload, indiscriminate iron supplementation in late preterm infants is debatable. This study aimed to evaluate the effect of a locally implemented guideline regarding individualized iron supplementation on the prevalence of ID(A) at the postnatal age of 4–6 months in Dutch preterm infants born between 32 and 35 weeks of gestational age (GA). Methods: An observational study comparing the prevalence of ID(A) at the postnatal age of 4–6 months in Dutch preterm infants born between 32 and 35 weeks of GA before (i.e. PRE-guideline group) and after (i.e. POST-guideline group) implementation of the local guideline. Results: Out of 372 eligible preterm infants, 110 were included (i.e. 72 and 38 in the PRE- and POST-guideline group, respectively). ID- and IDA-prevalence rates at 4–6 months of age in the PRE-guideline group were 36.1% and 13.9%, respectively, and in the POST-guideline group, 21.1% and 7.9%, respectively, resulting in a significant decrease in ID-prevalence of 15% and IDA-prevalence of 6%. No indication of iron overload was found. Conclusion: An individualized iron supplementation guideline for preterm infants born between 32 and 35 weeks GA reduces ID(A) at the postnatal age of 4–6 months without indication of iron overload.