Sabir Khan, Gul Nawab, Irshad Ahmad, Abdul Hameed, Ayub Khan, Zia Muhammad.
Frequency of Hypothyroxinemia in preterm versus term neonates.
Pak Paed J Jan ;30(3):119-23.

Objective: to determine the relative frequency of hypothyroxinemia in preterm versus term neonates from 3 to 7 days of age. Design: cross sectional analytic study. Place and duration of study: special care baby unit Khyber teaching hospital, Peshawar, in collaboration with IRNUM Hospital Peshawar from November 2004 to June 2005. Patient and methods: One hundred and one neonates age 3 to 7 days, including 52 preterm and 49 term babies were included in the study. Blood specimens for T4 and TSH assays were collected after taking informed consent from parents and tested in laboratory of IRNUM Hospital for serum T4 and TSH levels by radiommunoassy. Mean values of serum T4 and TSH levels in preterm and serum T4 and TSH levels in hypothyroxinemic preterm and term neonates were compared. Data was entered and analyzed on SPSS version 8. Results: Among 52 preterm neonates, 9 babies (17.3%) had serum T4 levels < 60 n mol/l compared to one baby out of 49 term neonates (2.04%). Mean values of serum T4 levels were lower in preterm neonates and values of serum TSH were not proportionately increased in these babies, while in one full term baby lower T4 level was associated with increased level of serum TSH. (High level of TSH was defined> 4.0 uIU/ml and low level of serum T4 was defined as < 60 nmol/l). Among 9 preterm babies with hypothyroxinemia who were called at later ages for follow up, parents of 2 babies agreed to give blood specimen and serum levels of T4 and TSH, which were normal in the babies (reflecting transient hypothyroxinemia of preterm). Conclusion: Hypothyroxinemia without significant hyperthyropinemia is relatively common in preterm than term neonates during the first weeks of life. It seems to be transient. Further studies are required to determine the risks and benefits of thyroxine therapy in preterm infants.

PakMediNet -Pakistan's largest Database of Pakistani Medical Journals - http://www.pakmedinet.com