[Analysis of influencing factors of transient hypothyroxinemia and low T3 syndrome in premature infants].

Objective: To investigate the influencing factors of transient hypothyroxinemia (THT) and low T3 syndrome (LT3S) in premature infants.

Method: We have studied 418 premature infants whose gestational age was between 26 and 36 weeks.Serum thyronine (T4), triiodothyronine (T3) and thyrotropin (TSH) of them were detected on the fourteenth day approximately after birth. The patients were divided according to their serum T4, T3 and TSH into 3 groups (transient hypothyroxinemia, low T3 syndrome and normal). Then 20 Perinatal factors which may be associated with THT and LT3S were collected. The factors were analyzed by using Chi-square test and Logistic regression.

Result: Forty-nine infants were found suffering from THT, 35 infants suffering from LT3S, and 334 infants in normal group. The prevalence rate of THT was 11.7%, and the prevalence rate of LT3S was 8.4%. Among the 20 factors, the factors related to the incidence of THT were male gender (OR = 1.863, 95%CI 0.966-3.594), albumin (OR = 2.401, 95%CI 1.294-4.455), dopamine (OR = 3.295, 95%CI 1.110-9.783) and those related to the incidence of LT3S were male gender (OR = 2.592, 95%CI 1.171-5.736), gestational age ≤ 28 wk (OR = 3.503, 95%CI 1.275-9.627).

Conclusion: Male gender, albumin and dopamine are perinatal risk factors of THT, meanwhile, male gender and gestational age ≤ 28 wk are perinatal risk factors of LT3S.With the use of risk factors identified in our study, it may be possible to separate infants having the highest risk of THT and LT3S, so as to form optimizing treatment strategies.