Circulating RNA Transcriptome of Pregnant Women with TSH Just Above the Trimester-Specific Reference and its Correlation with the Hypertensive Phenotype.

During gestation, a woman's body undergoes physiological changes that alter thyroid function. Pregnant women with hypothyroidism may exhibit gestational complications, including hypertension and preeclampsia. We investigated differentially expressed genes (DEGs) in circulating RNAs from pregnant women with TSH levels just above the normal range to determine the impact of a mild elevation of TSH in pregnancy. We selected three women with healthy thyroid pregnancy (HTP), three pregnant women with gestational hypothyroidism (GHT), and three nonpregnant women (NPG) to construct transcriptome libraries. We also compared our results with data from the GEO dataset and DisGeNET. We identified 1500 DEG in GHT and 1656 DEG in HTP. From GEO dataset, we recognized 453 DEGs in trimester-specific plasma RNA, 1263 DEGs in placental tissues from healthy women, 1031 DEGs from preeclamptic uteroplacental tissues and 1657 DEGs from placental tissues from severely preeclamptic women. In this scenario, 12.26% and 12.86% genes were shared between these datasets in GHT and HTP, respectively. We stablished 62 genes in GHT DEGs related to hypertensive phenotype hallmarks. In conclusion, even in women with a mild TSH increment, we were able to detect some DEGs that could be associated with a hypertensive phenotype.

Recent recommendations from ATA guidelines to define the upper reference range for serum TSH in the first trimester match reference ranges for pregnant women in Rio de Janeiro.

OBJECTIVES: American Thyroid Association (ATA)'s new guidelines recommend use of population-based trimester-specific reference range (RR) for thyrotropin (TSH) in pregnancy. The aim of this study was to determine first trimester TSH RR for a population of pregnant women in Rio de Janeiro State. SUBJECTS AND METHODS: Two hundred and seventy pregnant women without thyroid illness, defined by National Academy of Clinical Biochemistry, and normal iodine status were included in this sectional study. This reference group (RG) had normal median urinary iodine concentration (UIC = 219 µg/L) and negative anti-thyroperoxidase antibodies (TPOAb). Twin pregnancy, trophoblastic disease and use of drugs or supplements that influence thyroid function were excluded. In a second step, we defined a more selective reference group (SRG, n = 170) by excluding patients with thyroiditis pattern on thyroid ultrasound and positive anti-thyroglobulin antibodies. This group also had normal median UIC. At a final step, a more selective reference group (MSRG, n = 130) was defined by excluding any pregnant women with UIC < 150 µg/L. RESULTS: In the RG, median, 2.5th and 97.5th percentiles of TSH were 1.3, 0.1, and 4.4 mIU/L, respectively. The mean age was 270 ± 5.0 and the mean body mass index was 25.6 ± 5.2 kg/m2. In the SRG and MSRG, 2.5th and 975th percentiles were 0.06 and 4.0 (SRG) and 0.1 and 3.6 mIU/L (MSRG), respectively. CONCLUSIONS: In the population studied,TSH upper limit in the first trimester of pregnancy was above 2.5 mIU/L. The value of 3.6 mIU/L, found when iodine deficiency and thyroiditis (defined by antibodies and ultrasound characteristics) were excluded, matches recent ATA guidelines.

Recent recommendations from ATA guidelines to define the upper reference range for serum TSH in the first trimester match reference ranges for pregnant women in Rio de Janeiro

ABSTRACT Objectives: American Thyroid Association (ATA)'s new guidelines recommend use of population-based trimester-specific reference range (RR) for thyrotropin (TSH) in pregnancy. The aim of this study was to determine first trimester TSH RR for a population of pregnant women in Rio de Janeiro State. Subjects and methods: Two hundred and seventy pregnant women without thyroid illness, defined by National Academy of Clinical Biochemistry, and normal iodine status were included in this sectional study. This reference group (RG) had normal median urinary iodine concentration (UIC = 219 μg/L) and negative anti-thyroperoxidase antibodies (TPOAb). Twin pregnancy, trophoblastic disease and use of drugs or supplements that influence thyroid function were excluded. In a second step, we defined a more selective reference group (SRG, n = 170) by excluding patients with thyroiditis pattern on thyroid ultrasound and positive anti-thyroglobulin antibodies. This group also had normal median UIC. At a final step, a more selective reference group (MSRG, n = 130) was defined by excluding any pregnant women with UIC < 150 μg/L. Results: In the RG, median, 2.5th and 97.5th percentiles of TSH were 1.3, 0.1, and 4.4 mIU/L, respectively. The mean age was 270 ± 5.0 and the mean body mass index was 25.6 ± 5.2 kg/m2. In the SRG and MSRG, 2.5th and 975th percentiles were 0.06 and 4.0 (SRG) and 0.1 and 3.6 mIU/L (MSRG), respectively. Conclusions: In the population studied,TSH upper limit in the first trimester of pregnancy was above 2.5 mIU/L. The value of 3.6 mIU/L, found when iodine deficiency and thyroiditis (defined by antibodies and ultrasound characteristics) were excluded, matches recent ATA guidelines.

Is an upper limit of 2.5 mUI/l for TSH appropriate for the first trimester of pregnancy among young TPO - women?

OBJECTIVES: The general purpose of this study is to assess the distribution among the various hormonal indices in young pregnant women with negative thyroid peroxidase antibodies and iodine sufficiency and classify them accordingly while comparing them to literature proposed reference values for the first trimester. METHODS: A sectional study was carried out, including 127 pregnant women enrolled at the prenatal outpatient clinic at the Nova Iguaçu General Hospital, in the period comprised between 2000 and June 2007. They were submitted to TSH, free T(4), total T(4), TBG, and thyroid peroxidase antibody determinations. RESULTS: A median equal to 38.7 microg/ml was observed for TBG; TSH values varied between 0.02 and 5.84 mcUI/ml, with a median of 1.25 mcUI/ml. For total T(4) and free T(4), median values were, respectively 10.3 microg/dl and 1.20 ng/dl. Thirteen patients out of 115 displayed a TSH serum level above 2.5 mUI/ml. CONCLUSIONS: Patients with subclinical hypothyroidism classified by this new cutoff (serum TSH concentration between 2.5 mUI/l and the upper limit of the reference range), chiefly ATPO-negative young women display no need for treatment as there is no evidence that this condition is associated with maternal and fetal complications.

Hormona estimulante de la tiroides

La hormona estimulante de la tiroides- TSH por throid stimulating hormone-, liberada por la hipófisis anterior, es principal regulador de la función tiroidea. La secreción de la TSH es controlada por el hipotálmo mediante la hormona liberadora de tirotropina - TRH por thyrotropin releasing hormone-. A su vez, este sistemea regula la liberación de las hormonas tiroides: Tiroxina- T4- y tirotropina- T3-. En la producción de la TSH existe un mecanismo de retroalimentación negativo, que es sensible a las concentraciones de las hormonas tiroideas circulantes, T3 y T4, controladas por el hipotálamo. Colectivamente este sistema se denomina eje hipotálamo-hipofisiario-tiroideo. Cualquier alteraciónen la función del eje influye sobre los niveles sanguíneos de la T4 y T3.