Universal Predictive Criteria for Neonatal Overt Thyrotoxicosis Requiring Treatment

Abstract

The universal predictive criteria for neonatal overt thyrotoxicosis requiring treatment were examined in 108 neonates (including a pair of twins) born to mothers with Graves' disease (36 patients under treatment with antithyroid drugs [group A] and 71 in remission [group B]). Anti-thyroid-stimulating hormone (TSH) receptor antibody activity was measured by both radioreceptor assay (TSH-binding inhibitor immunoglobulin [TBII]) and biologic stimulation assay (thyroid stimulating antibody [TSAb]). For generalization of the predictive criteria, the expression of TBII activity was standardized using standard serum made taking units of Medical Research Council long-acting thyroid stimulator, standard B as a reference, and expression of TSAb activity was standardized using bovine TSH as a standard. TBII activity was positive in 22 mothers at delivery, and TSAb activity was positive in 18. In 12 cases, both activities were positive. Both the TBII and the TSAb activity of maternal serum at delivery correlated well with that of the cord serum. Neonatal thyrotoxicosis occurred in 9 of 108 neonates (8%), of whom five (5%) had clinical overt symptoms requiring antithyroid drug treatment. In all nine cases the TBII and TSAb activities were both positive, but no neonate without TBII or TSAb activity developed thyrotoxicosis. The prediction rate (42%) of neonatal overt thyrotoxicosis was higher when both TBII and TSAb were measured than when only TBII (23%) or TSAb (28%) was measured. Clinical overt thyrotoxicosis could be predicted in five of six neonates (83%) of mothers when the cutoff levels of antibody activities were increased to a TBII activity of above 8 U/ml and TSAb activity of above 1.0 TSH microUEq.(ABSTRACT TRUNCATED AT 250 WORDS)

Predictive value of maternal second-generation thyroid-binding inhibitory immunoglobulin assay for neonatal autoimmune hyperthyroidism

“…Individual cases are shown in Table 2. The median age of the women at the beginning of pregnancy was 31 years (range, [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. Twenty mothers of 21 neonates (one twin pregnancy) had a past history of GD.…”

Fetal neonatal hyperthyroidism: diagnostic and therapeutic approachment

“…However, this rate increases to 2-10% when biochemical hyperthyroidism without clinical reflections accompanies (3). Neonatal hyperthyroidism was found in 8% of babies of 108 mothers with Graves' disease, 71 of whom were in remission and 36 were receiving antithyroid treatment, but a severe clinical picture was observed in 5% of the babies (20). Mortimer et al (21) found the picture of hyperthyroidism with a rate of 8% in babies born from 48 mothers with Graves' disease, 44 of whom were in an active state.…”

“…Rarely, the stimulatory antibodies in the patient may be transformed into blocking antibodies or vice versa (8). Measurement of TSHR antibodies is initiated in the [20][21][22][23][24] th gestational week because the fetal TSH receptors start to respond from the 20 th week. A 3-5-fold increase in the stimulatory antibodies shows the risk of fetal hyperthyroidism (7).…”

“…Ten percent of the mother's level is transferred to the fetus in the [17][18][19][20][21][22] th gestational week and 50% is transferred to the fetus in the 28 th -32 nd weeks. Subsequently, the level in the fetus gradually increases and exceeds the mother's level in the term newborn (14).…”

Kinetic analyses of changes in serum TSH receptor antibody values after total thyroidectomy in patients with Graves’ disease

“…five times the upper limit of the normal range [1,[20][21][22] or > 10 IU/L [15]. We therefore used 10 IU/L as the cut-off value for TRAb in the present study.…”