title: Polycythemia in the newborn.
abstract: Polycythemia is defined as a venous hematocrit above 65%. The relationship between viscosity and hematocrit is almost linear till 65% and exponential thereafter. Increased viscosity of blood is associated with symptoms of hypo-perfusion. The hematocrit in a newborn peaks at 2 hours of age and decreases gradually after that. The etiology of polycythemia is related either to intra-uterine hypoxia or secondary to fetal transfusion. Clinical features related to hyperviscosity may affect all organ systems and this entity should be screened for in high-risk infants. Polycythemia maybe symptomatic or asymptomatic and guidelines for management of both types are provided in the protocol.
authors.affiliation: Division of Neonatology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Upadhyay
authors.forename: Rajiv
authors.initials: R
authors.lastname: Aggarwal
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Deorari
authors.forename: Vinod K
authors.initials: VK
authors.lastname: Paul
mesh_terms: D001809:Blood Viscosity; D006400:Hematocrit; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D011086:Polycythemia / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology / Q000628:therapy*