Descriptive study of the complete blood count in newborn infants with Down syndrome.

The usefulness of the complete blood count (CBC) during the first week of life in infants with Down syndrome (DS) has been recognized; however, studies are limited and have evaluated only some of the parameters of the CBC. Here, we report a prospective study of 135 infants with cytogenetically confirmed DS and a reference group of 226 infants without birth defects all born during the period 2009-2015 at the Dr. Juan I. Menchaca Civil Hospital of Guadalajara (Guadalajara, Mexico). The goal was to evaluate hematological findings in the CBC during the first 7 days of life, interpreted according to gestational and postnatal age. Data were analyzed using multivariate logistic regression analysis expressed as adjusted odds ratio (aORs) with 95% confidence intervals (95% CIs). Infants with DS had a significantly higher risk for polycythemia (aOR = 12.4, 95% CI: 4.6-33.3), macrocytosis (aOR = 15.9, 95% CI: 1.8-143.4), high values of mean corpuscular hemoglobin (aOR = 36.4, 95% CI: 4.5-294.9), anisocytosis (red blood cells of unequal size) (aOR = 3.9, 95% CI: 2.1-7.6), thrombocytopenia (aOR = 32.4, 95% CI: 15.2-68.9), white blood cell (WBC) count ≥30 × 10 /µl (aOR = 19.4, 95% CI: 4.1-91.5), lymphocytosis (aOR = 73.3, 95% CI: 9.5-565.4), and basophilia (aOR = 16.8, 95% CI: 1.9-151.5). Overall, 74% of infants with DS in our study had polycythemia, thrombocytopenia, WBC count >30 × 10 /µl, or lymphocytosis (aOR = 35.6, 95% CI: 18.8-79.2). Compared with those in other studies, our infants with DS had distinctive hematological findings including a lower frequency of thrombocytopenia, infrequent neutrophilia, and frequent lymphocytosis and neutropenia. This suggests ethnic, socioeconomic, or nutritional differences. © 2017 Wiley Periodicals, Inc.