Clinical aspects of morphological investigation of fetal thyroid glands

The investigation of 121 thyroid glands offetuses and neonates of mothers who live in Saint-Petersburg was carried out. The paper analyzes intra and postnatal fatal outcomes taking account оf gestational andpostnatal age. The role of thyroid glands adaptive function emaciation in thanatogenesis in case of asphyxia was demonstrated. On the basis of the study practical recommendations are suggested.

Endocrinology in pregnancy

This chapter covers both the normal and abnormal changes to the endocrine system during pregnancy. It begins with the thyroid in pregnancy, covering maternal hyperthyroidism, hyperemesis gravidarum, overt and subclinical maternal hypothyroidism, post-partum thyroid dysfunction, and fetal thyroid diseases owing to maternal thyroid disorders. Calcium metabolism, thyroid cancer, hypoparathyroidism, and lactation associated osteoporosis. Secondly, the pituitary gland in pregnancy is focused on, covering prolactinoma, Cushing’s Syndrome, acromegaly, non-functioning pituitary adenoma, hypopituitarism, and Diabetes Insipidus. Pre-existing adrenal disorders during pregnancy and alterations to management are also included.

Urinary Iodine Status at Delivery in Rural Pregnant Mothers from KONKAN Region of India (BKLWHANC-2)

Adequate iodine is necessary in pregnancy for normal maternal as well as fetal thyroid function. Fetus cannot produce thyroid hormone so it is exclusively dependent on mother. During pregnancy, iodine demand is increased by 50%. An adequate intake of dietary iodine in pregnancy is essential for the normal neurodevelopment of the offspring. We measured urinary iodine concentrations in 220 pregnant women who reported for delivery at a rural hospital in the KONKAN region of the State of Maharashtra, India. The mean age and gestation at delivery were 26.9 years and 38.2 weeks respectively. The observed median UIC was 84.6μg/l. Urinary iodine of mother was not associated with neonatal anthropometric measurements (weight, length and head circumference). We have found low median UIC levels at delivery among pregnant women. The increased demand in pregnancy could be met by iodine supplementation or increasing iodine content in the salt. The burden of poor iodine status in pregnant women will further adversely affect the fetal neurodevelopment. There should be universal screening of every pregnant woman for the identification of iodine status. A simple strategy of improving iodine content in the salt beyond the current recommendation for pregnant women might be beneficial for mother as well as fetus but continuous monitoring for adequate iodine is warranted.

Involvement of Thyroid Hormones in Brain Development and Cancer

The development and maturation of the mammalian brain are regulated by thyroid hormones (THs). Both hypothyroidism and hyperthyroidism cause serious anomalies in the organization and function of the nervous system. Most importantly, brain development is sensitive to TH supply well before the onset of the fetal thyroid function, and thus depends on the trans-placental transfer of maternal THs during pregnancy. Although the mechanism of action of THs mainly involves direct regulation of gene expression (genomic effects), mediated by nuclear receptors (THRs), it is now clear that THs can elicit cell responses also by binding to plasma membrane sites (non-genomic effects). Genomic and non-genomic effects of THs cooperate in modeling chromatin organization and function, thus controlling proliferation, maturation, and metabolism of the nervous system. However, the complex interplay of THs with their targets has also been suggested to impact cancer proliferation as well as metastatic processes. Herein, after discussing the general mechanisms of action of THs and their physiological effects on the nervous system, we will summarize a collection of data showing that thyroid hormone levels might influence cancer proliferation and invasion.

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.

Evaluation of TRAb and TSI Leves and Thyroid Function in Pregnant Women With Graves’ Disease and Newborn: Preliminary Data

Introduction: GD, mediated by TSH receptor-stimulating immunoglobulins (Igs) (rTSH), can lead to fetal thyroid dysfunction through the passage of Igs through the placenta during pregnancy. TRAb levels, used for prognostic evaluation, measure rTSH-stimulating and blocking Igs while TSI evaluates only as stimulating Igs. Objective: To prospectively evaluate pregnant women with DG and newborns (NB) by measuring TRAb and TSI and their correlation with thyroid function and postpartum complications. Methods: The patients were evaluated during pregnancy and the puerperium and the respective newborns. TSH, thyroid hormones and TRAb were evaluated by electrochemiluminescent method (Roche) and TSI by chemiluminescent assay (Siemens). TRAb<1.75IU/L and TSI<0.55IU/L were considered negative. Results: Nine patients were evaluated, with a mean age of 27.4±5.7 years: 6 had TRAb and TSI positive in the 1st trimester (1st-tri), when they maintained or started DAT; one with both negative (without DAT) and one with weakly positive TSI, when DAT was suspended. These last two remained euthyroid during pregnancy and puerperium. Of the first 6, 4 were evaluated in the 3rd-tri: three negative for TRAb and maintained positive TSI, 2 in low leves and one for high titles, when DAT was suspended or reduced; one kept both at very high levels. A patient with post-DT hypothyroidism, performed 3 years ago, using levothyroxine, evaluated in the 3rd-tri, had a negative TRAb and a highly positive TSI and remained so after pregnancy. The two patients who presented weakly positive TSI in the 3rd-tri evolved with their negative results and without DAT in the puerperium. The patient with TSI in high titers evolved with elevated levels as well as positive TRAb titers and postpartum decompensation. The patient with positive antibodies remained compensated for stable doses of DAT. Four NB were evaluated: all healthy, with normal thyroid function and negative TRAb. TSI was positive in 2 in the postpartum period; TSI was negative afterwards, while in the other 2 both antibodies were negative. Conclusions: TSI was not associated with thyroid dysfunction in NB, although it was associated with worsening hyperthyroidism in pregnant women, when at high titers. Positive TSI at low levels were not associated with worsening of the condition, which requires further studies to determine the cutoff point for assessing treatment suspension.

Congenital Hypothyroidism Can Dictate the Mode of Delivery and Intra-labor Medication Usage

Pregnancy and parturition reflect the complex interaction between physiologic conditions of the mother and her offspring, and fetal health characteristics may affect maternal health throughout pregnancy and delivery. We investigated the characteristics of the mother-infant dyad of term infants detected by the National Newborn Screening Program as having congenital hypothyroidism (CH) (131 out of 108,717; 0.12%). Three years of surveillance in our Pediatric Endocrine Clinic revealed that 65 had transient CH and 66 had permanent CH. A higher proportion of deliveries of CH infants required vacuum assistance, and more infants with CH were born through a cesarean section compared to the general population (p<0.001). Medication during labor also differed, with higher rates of oxytocin (p<0.001) and antibiotics (p=0.008) administered to mothers of CH infants. A multivariate logistic regression model revealed an increased demand for oxytocin administration during the labor of a CH infant in a hypothyroidism severity-dependent manner, expressed as a threefold risk associated with permanent but not transient CH. Our findings of increased utilization of medical interventions during the labor and delivery of CH infants suggest that the prenatal fetal thyroid function affects the development and progress of labor and delivery, in response to oxytocin.

X-Ray and Molecular Imaging During Pregnancy and Breastfeeding—When Should We be Worried?

Some of the ethically most sensitive issues in radiation protection arise at imaging of pregnant—and potentially pregnant—patients and of newborn. This article reviews the current literature and recommendations on imaging during pregnancy and breastfeeding. Risks related to alternative non-ionizing radiation methods are also considered. With few exceptions, exposure of the fetus through radiography, computed tomography (CT) and nuclear medicine imaging can be limited to safe levels, although studies such as abdominal-pelvic CT cannot avoid significant exposure to fetuses. Eight to 10 weeks post-conception, the fetus has a thyroid which starts to concentrate iodide having crossed the placenta barrier resulting in unacceptably high doses to the fetal thyroid after administration of 131I- and even 123I-iodide and other radiopharmaceuticals with a high content of free radioiodine. Many radiopharmaceuticals are excreted through breast milk. Breastfeeding interruption recommendations should be followed to keep the effective dose to the infant below 1 mSv.

Excessive Prenatal Supplementation of Iodine and Fetal Goiter: Report of Two Cases Using Three-dimensional Ultrasound and Magnetic Resonance Imaging

Fetal thyroid complications in pregnancy are uncommon, and are commonly related to the passage of substances through the placenta. The excessive iodine intake during the pregnancy is a well-known mechanism of fetal thyroid enlargement or goiter, and invasive procedures have been proposed for the treatment of fetal thyroid pathologies. In the present report, we demonstrate two cases from different centers of prenatal diagnosis of fetal thyroid enlargement and/or goiter in three fetuses (one pair of twins, wherein both fetuses were affected, and one singleton pregnancy). The anamnesis revealed the ingestion of iodine by the patients, prescribed from inadequate vitamin supplementation. In both cases, the cessation of iodine supplement intake resulted in a marked reduction of the volume of the fetal thyroid glands, demonstrating that conservative treatment may be an option in those cases. Also, clinicians must be aware that patients may be exposed to harmful dosages or substances during pregnancy.