Analysis Of CH Specialy In Preterm Infants
Up to this date, a few approaches have been introduced in order to reach this goal. One is reducing cutoff value in order to increase the sensitivity of the screening test; another is repetition of the screening test in low birth weight and pre-term infants in order not to miss delayed rise of TSH. Moreover, some studies have suggested considering …show more content…
Lowering screening cutoff of TSH and using cutoffs according to the gestational age were the recommendation of 11.11%32,33,38,40and 8.3%15,18,40 of the reviewed studies, respectively. Some of the studies (13.9%) recommended using both TSH and T4 for screening of preterm infants14,19,20,39,42 and some had not any recommendation for CH screening and only reported their findings about normalization time of TSH and T4 in this group of …show more content…
Thus, a cutoff level of 10 mU/L can improve the screening test for congenital hypothyroidism, whether in full-term or pre-term infants.36
Another suggested approach is repetition of the screening test in order to find cases with delayed TSH rise who were missed using the primary test. However, there are disputes on the suitable time for the 2nd test.
Chung et al who studied 105 infants in South Korea, believe repetition of the test in pre-term newborns is necessary, since they may temporary have a normal thyroid profile in the first days of their life. They recommended 2nd to 4th weeks of life as the suitable time for the 2nd test.26 In 2010 Chee et al measured FT4 and TSH levels in low birth weight infants in the age one, two and four weeks, and proposed that TSH reaches its maximum level averagely in the age of 2.4 weeks.34
In 2012, Niwa’s team studied on 47 very low birth weight infants in Kyoto Hospital, Japan, and proposed that measuring TSH level at the age of two weeks can be helpful in evaluating transient hypothyroxinemia of prematurity and in prediction of the occurrence of delayed rise in