Transient Hypothyroxinaemia in Full Term Low Birth Weight Neonates

This prospective study was done in Combined Military Hospital, Dhaka from July 2002 to June 2003 todocument the postnatal changes of thyroid hormones in full term low birth weight (LBW) neonates. Theparameters were- serum TT4 (total thyroxin), TT3 (total triiodothyronine), FT4 (free thyroxin) and TSH(thyroid stimulating hormone). Twenty seven healthy full term neonates formed the control group (group A)who were studied on day 5 to observe the base line data. Study group (group B) consisted of 27 low birthweight (LBW) neonates. They were studied twice on day 5 (B1) and day 45 (B2). The mean ± SD gestational agewas 38.41±0.93 and 38.63±1.08 weeks in group A and B respectively. The mean ± SD birth weight were3.41±0.55 and 2.11±0.33 kg in group A and B respectively and the difference was statistically significant (p<0.0001). All neonates of group A had normal serum levels of TT4, TT3, FT4 and TSH on day 5 but in LBW fullterm neonates though FT4 level remained within normal range, 48% neonates of group B had significantlydecreased levels of TT4, TT3 and TSH (p<0.001) but on day 45 all of these hormone levels were significantlyincreased (p<0.001) and attained normal values. This study showed that 48% LBW neonates had transienthypothyroxinaemia on day 5 which was corrected spontaneously by day 45.Key words: Hypothyroxinaemia; Low birth weight (LBW).DOI: 10.3329/jafmc.v6i1.5984Journal of Armed Forces Medical College, Bangladesh Vol.6(1) 2010 p.8-11