Associations of maternal oestradiol, cortisol, and TGF-β1 plasma concentrations with thyroid autoantibodies during pregnancy and postpartum

Thyroid Predictors of Postpartum Mood Disorders

Postpartum mood disorders (PMD) are currently among the leading causes of maternal postpartum morbidity and mortality. PMD include the conditions of postpartum blues (PB), postpartum depression (PPD), and postpartum psychosis. The pathogenesis of PMDs are ambiguous, and there are no reliable prenatal predictive markers despite current research efforts. Even though reliable indicators have not been found, leading ideas suggest an etiology of hormonal fluctuations. Although thyroid markers have long been linked to psychiatric disorders such as major depressive disorder (MDD), how they correlate with PMDs is still unclear. This study aimed to evaluate the pathophysiological link between thyroid function, PMDs, and the usefulness of thyroid markers as indicators of their occurrence and severity. The methodology consisted of a narrative literature review. Several inclusion and exclusion criteria were used to filter the results of literature searches in PubMed. Studies were included if they discussed any marker related to thyroid endocrinology in relation to the incidence or pathophysiology of any PMD. Both primary and secondary analyses were included. The permissive inclusion criteria were used due to the relative scarcity of research on the topic and the ambiguous pathophysiology of PMD. The results demonstrated the potential utility of thyroid autoimmunity as a predictor of late-onset PPD. Hypothyroidism, low euthyroid hormone levels, and the presence of thyroid autoantibodies were correlated with increased incidence of PPD and late postpartum depressive symptoms, past the timeline of PB. Most notably a rapid postpartum drop in cortisol level may precipitate thyroid autoimmunity in anti-thyroid peroxidase (TPO) antibody positive women, which could eventually produce a hypothyroid phase associated with depressive symptoms. There was insufficient evidence to suggest a relationship with postpartum psychosis. In conclusion, the exact pathophysiological mechanisms of PMDs remain ambiguous, but TPO-antibodies in the third trimester may be a predictor of late PPD.

The role of transforming growth factor beta in thyroid autoimmunity: current knowledge and future perspectives

The complex mechanisms, which are related to the pathophysiology and the development of autoimmune thyroid diseases, involve transforming growth factor beta (TGF-β) and its interplay with the immune system. The aim of this review is to examine the role of TGF-β regarding thyroid autoimmunity and explore the potent role of this molecule either as a diagnostic or prognostic marker or a therapeutic target regarding autoimmune thyroid diseases. TGF-β is clearly a master regulator of the immune response, exerting either inhibitory or facilitatory effects on cells of the immune system. Thus, this molecule is involved in the pathogenesis and development of autoimmune thyroid diseases. Recent research has revealed the involvement of TGF-β in the pathophysiology of autoimmune thyroid diseases. The role of TGF-β in the development of autoimmune thyroid diseases varies, depending on its concentrations, the type of the activated TGF-β signalling pathway, the genetic predisposition of the patient and the pathophysiologic stage of the disease. TGF-β could emerge as a useful diagnostic or prognostic marker for the evolution of thyroid autoimmunity. Promising perspectives for the effective therapeutic use of TGF-β regarding thyroid autoimmunity exist. The main treatment approaches incorporate either enhancement of the immunosuppressive role of TGF-β or inhibition of its facilitatory role in the autoimmune thyroid diseases. Further research towards deeper understanding of TGF-β physiology and clinical application of its possible therapeutic role regarding thyroid autoimmunity is needed.

Associations of Thyroid Hormones Profile During Normal Pregnancy and Postpartum With Anxiety, Depression, and Obsessive/Compulsive Disorder Scores in Euthyroid Women

Objective

Thyroid dysfunction (overt and subclinical) has been consistently linked to pregnancy adversity and abnormal fetal growth and development. Mood disorders such as anxiety, depression, and obsessive-compulsive disorder (OCD) are frequently diagnosed during pregnancy and at postpartum, and emerging evidence suggests association with impaired offspring neurodevelopment and growth. This study aimed to examine potential associations between thyroid function and mood symptoms during pregnancy and postpartum.

Design

This is a prospective study measuring thyroid hormones and assessing mood symptoms by employing specific questionnaires in the same cohort of 93 healthy pregnant women at the 24th (2nd trimester) and 36th (3rd trimester) gestational weeks and at the 1st postpartum week.

Methods

Serum thyroid hormones, TSH, anti-TPO, and anti-Tg antibodies were measured at the 24th (2nd trimester) and 36th (3rd trimester) gestational weeks and at the 1st postpartum week. Specific validated questionnaires were employed at the same time-points to assess separately symptoms of anxiety [Generalized Anxiety Disorder Inventory (GADI), Penn State Worry Questionnaire (PSWQ), STAI-State Anxiety inventory (STAI-S), STAI-Trait Anxiety Inventory (STAI-T)], depression [Edinburgh Postnatal Depression Scale (EPDS), Stein’s Blues Scale (BLUES), Beck Depression Inventory (BDI)], and obsessive compulsive disorder (OCD) [Yale-Brown Obsessive Compulsive scale (Y-BOCS)].

Results

At the 2nd trimester, GADI score correlated negatively with FT3 (p < 0.010, r = −0.545) and positively with TSH (p < 0.050, r = 0.837) concentrations; GADI, PSWQ, EPDS and Y-BOCS scores correlated negatively with FT4 concentrations (p < 0.010, r = −0.768; p < 0.010, r = −0.384; p < 0.050, r = −0.364; p < 0.010, r = −0.544, respectively). At the 3rd trimester, BLUES score correlated positively with rT3 concentrations (p = 0.00, r = 0.89); GADI, EPDS, and Y-BOCS scores correlated negatively with FT4 concentrations (p = 0.001, r = − 0.468; p = 0.036, r = −0.39; p = 0.001, r = −0.625, respectively); GADI, STAI-S, and Y-BOCS scores correlated positively with TSH concentrations (p = 0.015, r = 0.435; p = 0.024, r = 0.409 p = 0.041, r = 0.389, respectively). At postpartum, PSWQ, STAI-T, EPDS, and BDI scores correlated positively with rT3 concentrations (p = 0.024, r = 0.478; p = 0.014, r = 0.527; p = 0.046, r = 0.44; p = 0.021, r = 0.556, respectively, Y-BOCS score correlated positively with TSH (p = 0.045, r = 0.43), and BLUES score correlated positively with anti-TPO antibody concentrations (p = 0.070, r = 0.586).

Conclusion

The reported findings demonstrate positive associations between low-normal thyroid function at the 2nd and 3rd trimesters of pregnancy and postpartum with anxiety, depression, and OCD scores.

Lower educational status interferes with maternal iodine intake during both pregnancy and lactation

OBJECTIVE

To investigate factors affecting conscious iodine intake among pregnant and lactating women in a rural area in Hungary.

METHODS

Pregnant women were studied and followed during lactation. Urinary and breast milk iodine concentration (UIC and MIC) were measured by inductively coupled plasma mass spectrometry. Potential interfering factors, including age, educational status and smoking were assessed.

RESULTS

During pregnancy and lactation, mild iodine deficiency was observed; median UIC were 66 and 49 µg/L, respectively. Educational status was found to be a strong determinant of both iodine nutrition and smoking status during pregnancy (P < 0.01 and P < 0.001) and lactation (P < 0.001 and P < 0.01). While smoking and non-smoking lactating mothers had similar concentrations of urinary iodine (median UIC: 47 and 51 µg/L, P = 0.95), the breast milk of smoking mothers contained less iodine (median MIC: 150 and 203 µg/L, P = 0.03).

CONCLUSIONS

Both low iodine intake and smoking contribute to the higher risk of iodine deficiency in women with lower educational status. In smokers, MIC is often low in spite of normal UIC, presumably due to the iodine transport blocking effect of the cigarette smoke towards breast milk; normal UIC may be misinterpreted as sufficient iodine supply towards the child. Antenatal health promotion strategies should focus on young women with lower educational status, even in regions where sufficient iodine intake has been achieved in non-pregnant adults.

TGF-β Physiology as a Novel Therapeutic Target Regarding Autoimmune Thyroid Diseases: Where Do We Stand and What to Expect

Transforming growth factor beta (TGF-β), as a master regulator of immune response, is deeply implicated in the complex pathophysiology and development of autoimmune thyroid diseases. Based on the close interplay between thyroid autoimmunity and TGF-β, scientific interest was shifted to the understanding of the possible role of this molecule regarding the diagnosis, prognosis, and therapy of these diseases. The main aim of this review is to present research data about possible treatment options based on the role of TGF-β in thyroid autoimmunity. Suggested TGF-β-mediated therapeutic strategies regarding autoimmune thyroid diseases include either the enhancement of its immunosuppressive role or inhibition of its facilitatory role in thyroid autoimmunity. For example, the application of hr-TGF-β can be used to bolster the inhibitory role of TGF-β regarding the development of thyroid diseases, whereas anti-TGF-β antibodies and similar molecules could impede its immune-promoting effects by blocking different levels of TGF-β biosynthesis and activation pathways. In conclusion, TGF-β could evolve to a promising, novel therapeutic tool for thyroid autoimmunity.

The Effect of Thyrotropin-Releasing Hormone and Antithyroid Drugs on Fetal Thyroid Function

A euthyroid pregnant woman will normally have a fetus that displays normal fetal development. However, studies have long demonstrated the role of T3 (Triiodothyronine), T4 (Thyroxine), and TSH (Thyroid Stimulating Hormone) and their degree of penetrability into the fetal circulation. Maternal thyrotropin-releasing hormone (TRH) crosses the placental site and, from mid-gestation onward, is able to promote fetal TSH secretion. Its origin is not only hypothalamic, as was believed until recently. The maternal pancreas, and other extraneural and extrahypothalamic organs, can produce TRH variants, which are transported through the placenta affecting, to a degree, fetal thyroid function. Antithyroid drugs (ATDs) also cross the placenta and, because of their therapeutic actions, can affect fetal thyroid development, leading in some cases to adverse outcomes. Furthermore, there are a number of TRH analogues that share the same properties as the endogenous hormone. Thus, in this narrative review, we highlight the interaction of all the above with fetal growth in uncomplicated pregnancies.

Graves' disease

Graves' disease (GD) is an autoimmune disease that primarily affects the thyroid gland. It is the most common cause of hyperthyroidism and occurs at all ages but especially in women of reproductive age. Graves' hyperthyroidism is caused by autoantibodies to the thyroid-stimulating hormone receptor (TSHR) that act as agonists and induce excessive thyroid hormone secretion, releasing the thyroid gland from pituitary control. TSHR autoantibodies also underlie Graves' orbitopathy (GO) and pretibial myxoedema. Additionally, the pathophysiology of GO (and likely pretibial myxoedema) involves the synergism of insulin-like growth factor 1 receptor (IGF1R) with TSHR autoantibodies, causing retro-orbital tissue expansion and inflammation. Although the aetiology of GD remains unknown, evidence indicates a strong genetic component combined with random potential environmental insults in an immunologically susceptible individual. The treatment of GD has not changed substantially for many years and remains a choice between antithyroid drugs, radioiodine or surgery. However, antithyroid drug use can cause drug-induced embryopathy in pregnancy, radioiodine therapy can exacerbate GO and surgery can result in hypoparathyroidism or laryngeal nerve damage. Therefore, future studies should focus on improved drug management, and a number of important advances are on the horizon.