Prevalence of microcytosis in cord blood samples and admitted

The study was established to define the prevalence of neonatal microcytosis and to estimate the incidence rate of alpha-thalassemia as its leading cause, in Tehran, Iran.
Overall, 800 neonates were selected from two populations of newborns and admitted neonates. Three hundred and sixty-one cord blood samples were obtained from deliveries in Mahdieh Hospital in April and May 2013. A second group of 439 neonates aged 1-5 days were subject to the study from admissions to the neonatal ward and neonatal intensive care units in Mahdieh Hospital between March 2011 and August 2014. All the included neonates were term, single, with normal birth weights. The admitted neonates suspected to have hemolytic anemia were excluded from the study. Microcytosis cut-off point was set at 95 fl.
Prevalence of microcytosis was 2.5% in cord blood samples and 7.7% in admitted neonates. The admitted neonates showed a 3.28-fold higher risk of microcytosis compared to newborns. The average mean corpuscular volume was 104.6 ± 4.5 fl in newborns and 103.2 ± 6.0 fl in the admitted neonates. The admitted neonates had smaller and lower numbers of erythrocytes with higher mean corpuscular hemoglobin.
Prevalence of neonatal microcytosis was lower than expected in healthy newborns based on some previous studies, and therefore, alpha-thalassemia carriership as the main leading cause of neonatal microcytosis does not appear to be an urgent issue for mass screening to be considered. Selective screening should be taken into account as a more cost-effective option in neonatology wards.