Background-aim: Normal thyroid function during pregnancy is critical for fetal development. Deficient maternal thyroid hormone levels are associated with impaired neuropsychological development in childhood, premature birth, preeclampsia and fetal mortality. Conversely, excessive maternal thyroid levels have been linked to fetal loss, disturbed fetal growth, preeclampsia and preterm delivery. Recent consensus guidelines do not advocate universal thyroid function screening during pregnancy. The aim of the present study was to investigate the prevalence of undiagnosed thyroid disease in pregnancy.
Subjects and methods: During 2009, we studied 178 consecutive pregnant women (mean age±S.D. 28.26±5.56 years), during their antenatal visit between 26 and 28th week of pregnancy. Serum levels of TSH, free T3 and free T4 were measured.
Results: Median (range) values of TSH, FT4 and FT3 were 1.61 (0.116.4), 0.96 (0.711.53) and 3.77 (2.175.93), respectively. Of the 178 pregnant women, none presented hyperthyroidism or hypothyroidism. Nevertheless, 9 women (5.1%) reached the second trimester of pregnancy with subclinical hyperthyroidism (normal free T4 values and TSH values below normal) and 27 (15.2%) were found to have subclinical hypothyroidism (normal free T4 values and TSH values above normal).
Conclusions: There is still a high percentage of pregnant women that reach second trimester of pregnancy with undiagnosed thyroid disease. Although it remains controversial whether to screen for thyroid disease or not, it seems reasonable to screen women with a serum TSH, if they are pregnant or contemplating pregnancy.
Prague, Czech Republic
24 - 28 Apr 2010
European Society of Endocrinology