Hyperthyroidism and Pregnancy

Reference intervals for thyroid function from the fifth to seventh day of life in twin-pregnancy preterm neonates: an 8-year retrospective study

PURPOSE

The immature and developing hypothalamic-pituitary-thyroid axis leads to different levels of thyroid function in twin neonates, including free thyroxine (FT4), free triiodothyronine (FT3), and thyroid stimulating hormone (TSH) levels. No reference intervals for twins have been established until now. To compensate for this lack, we collected data and established this standard across different gestational ages (GAs) and sexes.

METHODS

A total of 273 pairs of neonates admitted to the NICU in Southeast China from 2015 to 2022 were included. Each pair was divided into Neonate A (relatively heavy birth weight (BW)) and Neonate B (relatively light BW). Their thyroid functions were analyzed to establish reference intervals and comparisons were made stratified by GA and sex.

RESULTS

The FT3, FT4, and TSH reference intervals in twin neonates with a GA of 26-36 weeks were as follows: Neonate A and B: 3.59 ± 0.99 and 3.57 ± 1.00 pmol/L; Neonate A and B: 17.03 ± 5.16 and 16.77 ± 5.29 pmol/L; and Neonate A and B: 4.097 ± 3.688 and 4.674 ± 4.850 mlU/L, respectively. There were significant differences between serum FT3 and FT4 reference intervals and GA (p < 0.05). The serum FT3 and FT4 reference intervals for male neonates were lower than those for female neonates in the 29-32-week group (p < 0.05).

CONCLUSION

This was the first study, to our knowledge, to establish reference intervals for thyroid function in twin neonates from the fifth to seventh day of life, which will be beneficial for the diagnosis and management of congenital hypothyroidism.

Early-pregnancy N-terminal pro-brain natriuretic peptide level is inversely associated with hypertensive disorders of pregnancy diagnosed after 35 weeks of gestation

Hypertensive disorders of pregnancy (HDP) are among the major causes of high maternal and fetal/neonatal morbidity and mortality rates. Patients with HDP have significantly elevated N-terminal pro-brain natriuretic peptide (NT-proBNP) levels at diagnosis; however, the NT-proBNP levels during early pregnancy are largely unknown. This study aimed to validate the association between HDP and NT-proBNP levels. This retrospective study evaluated 103 pregnant women who developed HDP diagnosed after 35 weeks of gestation and 667 who did not. The HDP group had significantly lower early-pregnancy NT-proBNP levels than the without HDP group. However, the two groups did not significantly differ in terms of the late-pregnancy NT-proBNP levels. After adjusting for confounding factors such as age, body mass index, parity, and blood pressure levels, high early-pregnancy NT-proBNP levels were associated with a lower HDP risk. Early-pregnancy NT-proBNP levels ≥ 60.5 pg/mL had a negative predictive value of 97.0% for ruling out HDP, with a sensitivity of 87.4% and specificity of 62.5%. In conclusion, elevated early-pregnancy NT-proBNP levels were associated with a lower HDP risk. Moreover, a cutoff point of ≥ 60.5 pg/mL for early-pregnancy NT-proBNP levels had a high negative predictive value and sensitivity for ruling out HDP. These findings can provide new clinical implications.

Fetal Hyperthyroidism Secondary to Maternal Basedow-Graves' Disease

Fetal hyperthyroidism is a rare prenatal disease and can be life-threatening. The diagnosis is based on ultrasound in mothers with a history of Basedow-Graves' disease and elevation of thyrotropin receptor antibodies (TRAbs) levels. The treatment consists of antithyroid drugs. We present a mother with Basedow-Graves' disease, treated with radioactive iodine 16 years ago. She had an unplanned pregnancy at the age of 29 years, and an elevation of TRAbs (21 U/L) was found at the sixth week of pregnancy. At 22 weeks of gestation, fetal ultrasound displayed tachycardia, goiter, exophthalmos, and suspicion of craniosynostosis, hence methimazole was started. Concomitantly, suppressed maternal thyroid-stimulating hormone (TSH) was found. Her daughter was born at 33 + 6 weeks showing clinical and laboratory findings of hyperthyroidism. Consequently, treatment with methimazole was prescribed. Normal thyroid function was documented in the mother after giving birth. Clear explanation has not been found for the alteration of maternal TSH during pregnancy.

The tortuous diagnosis of one case of neonatal hyperthyroidism

OBJECTIVE

To outline the clinical signs, diagnosis, and course of care for a single case of neonatal hyperthyroidism while also summarizing common diagnostic errors related to this condition.

METHODS

Medical records of the neonate of hyperthyroidism were collected and analyzed in combination with literature.

RESULTS

The neonate's mother had thyroid disease, but her thyrotropin receptor antibody (TRAb) levels were not monitored during pregnancy. The neonate exhibited typical symptoms of hyperthyroidism on the day of birth but was not diagnosed until 15 days later. Impaired liver (cholestasis, elevated liver enzymes) and cardiac function (pulmonary hypertension, right heart enlargement) are the main manifestations. Treatment with methimazole (1.0 mg /kg·d) and propranolol (2.0 mg /kg·d) led to recovery, and the neonate stayed in the hospital for 27 days before being discharged with medication. The diagnosis was temporary hyperthyroidism, and the medication was discontinued at 72 days of age.

CONCLUSION

It is important to strengthen the management of high-risk pregnant women with thyroid disease. Monitoring TRAb levels in both mothers and neonates should be done dynamically to enable early prediction and diagnosis of neonatal hyperthyroidism. Most neonates with hyperthyroidism have a good prognosis when timely and appropriate medical treatment is provided.

Comparison of the safety between propylthiouracil and methimazole with hyperthyroidism in pregnancy: A systematic review and meta-analysis

OBJECTIVE

The purpose of this meta-analysis was to assess the safety of the anti-thyroid drugs (ATDs) propylthiouracil (PTU) and methimazole (MMI) in the treatment of hyperthyroidism during pregnancy.

METHOD

From inception until June 2, 2022, all available studies were searched in PubMed, Web of Science, Cochrane, EBSCO, Embase, Scopus, and CNKI.

RESULT

Thirteen articles satisfying the inclusion criteria were examined. Our meta-analysis indicated that pregnant women treated with MMI had a higher risk of congenital anomalies than those treated with PTU (OR 0.80, 95%CI 0.69-0.92, P = 0.002, I2 = 41.9%). Shifting between MMI and PTU during pregnancy did not reduce the risk of birth defects compared to PTU alone (OR 1.18, CI 1.00 to 1.40, P = 0.061, I2 = 0.0%). There were no statistically significant differences in hepatotoxicity (OR 1.54, 95%CI 0.77-3.09, P = 0.221, I2 = 0.0%) or miscarriage (OR 0.89, 95%CI 0.72-1.11, P = 0.310, I2 = 0.0%) between PTU and MMI exposure.

CONCLUSION

The study confirmed propylthiouracil is a safer alternative to methimazole for treating hyperthyroidism in pregnant women, and it is appropriate to treat maternal thyroid disease with PTU during the first trimester of pregnancy. However, it is not clear whether switching between propylthiouracil and methimazole is a better option than treating PTU alone during pregnancy. Further studies on this matter may be needed to develop new evidence-based guidelines for the treatment of pregnant women with hyperthyroidism.

Associations between hyperthyroidism and adverse obstetric and neonatal outcomes: A study of a population database including almost 17,000 women with hyperthyroidism

OBJECTIVE

Large population-based studies on maternal hyperthyroidism's effect on antepartum, intrapartum, and neonatal complications are few. Most of these studies were small or did not evaluate a broad scope of possible complications. Therefore, a large population-based cohort study was conducted to study the associations between maternal hyperthyroidism and pregnancy and perinatal complications.

DESIGN

This is a retrospective population-based cohort study utilizing data from the Healthcare Cost and Utilization Project-Nationwide Inpatient Sample over 11 years from 2004 to 2014.

PATIENTS

16,984 deliveries to women with hyperthyroidism and 9,079,804 deliveries to mothers who did not suffer of hyperthyroidism.

METHODS

A cohort of all deliveries between 2004 and 2014 inclusively was created. Within this group, all deliveries to women with hyperthyroidism were the study group (n = 16,984) and the remaining deliveries were categorized as nonhyperthyroidism births and comprised the reference group (n = 9,079,804). The main outcome measures were pregnancy and perinatal complications.

RESULTS

Maternal hyperthyroidism was associated with several pregnancy and perinatal complications, including increased risks of gestational hypertension (adjusted odds ratio [aOR]: 1.236, 95% confidence interval [CI]: 1.045-1.462, p = .013) and preeclampsia (aOR: 1.190, 95% CI: 1.006-1.408, p = .042). These patients are more likely to experience preterm premature rupture of membranes (aOR: 1.322, 95% CI: 1.007-1.735, p = .044), preterm delivery (aOR: 1.287 95% CI: 1.132-1.465, p < .001), placental previa (aOR: 1.527, 95% CI: 1.082-2.155, p = .016), and suffer from venous thromboembolism (aOR: 2.894, 95% CI: 1.293-6.475, p = .010). As for neonatal outcomes, small for gestational age and stillbirth were more likely to occur in the offspring of women with hyperthyroidism (aOR: 1.688, 95% CI: 1.437-1.984, p < .001 and aOR: 1.647, 95% CI: 1.109-2.447, p = .013, respectively).

CONCLUSIONS

Women with hyperthyroidism are more likely to experience pregnancy, delivery, and neonatal complications. We found an association between hyperthyroidism and hypertensive disorders, preterm delivery, and intrauterine fetal death.

Recent Advances in Treatment of Recurrent Spontaneous Abortion

Importance

Recurrent spontaneous abortion (RSA) is a distressing condition experienced by approximately 1% of women trying to conceive. However, the treatment of RSA is a challenge both for clinicians and patients.

Objective

The aim of this review is to discuss the medical and surgical approach to the management of RSA, including those caused by anatomical, genetic, male, infectious, endocrine, and immune factors.

Evidence Acquisition

A literature search using MeSH terms for each topic was undertaken using PubMed, supplemented by hand searching for additional references. Retrieved articles were reviewed, synthesized, and summarized.

Results

Available treatments target hypothetical risk factors for RSA, although the effectiveness of many treatment options is controversial. Intervention should depend on the benefit-to-risk ratio of the proposed treatment.

Conclusions and Relevance

The etiology of RSA is heterogeneous, and patients often lack specific clinical manifestations, which has hindered the progress in predicting and preventing RSA to some extent. Despite intensive workup, at least 50% of couples do not have a clear underlying pathology. In addition, an evidence-based treatment is not available in most patients even if abnormal test results are present. Many new treatment directions are also still actively exploring; empirical and combined multiple treatments are still the main methods.

Target Audience

Obstetricians and gynecologists, family physicians.

Learning Objectives

After completing this activity, the learner should be better able to describe common risk factors for RSA; formulate individualized treatment plans to improve pregnancy outcomes; and propose supportive treatment recommendations for patients with unclear causes.

A hypothyroid mother after subtotal thyroidectomy delivered a newborn with hyperthyroidism from fetal stage: a case report

BACKGROUND

Neonatal hyperthyroidism is an extension of fetal disease. Most cases of neonatal hyperthyroidism are transient but may excessively harm multiple organ functions through the actions of maternal thyroid-stimulating hormone receptor antibodies on the neonatal thyroid gland.

CASE PRESENTATION

The hyperthyroid mother underwent subtotal thyroidectomy before pregnancy and regularly took levothyroxine to avoid hypothyroidism, but still had a high-level thyroid-stimulating hormone receptor antibody (TRAb). The neonate suffered from hyperthyroidism due to the transplacental TRAb. After a regular medication schedule of an antithyroid drug, combined with a β-blocker to control the ventricular rate, the infant gradually recovered, allowing normal motor and intellectual development.

CONCLUSIONS

Maternal subtotal thyroidectomy cannot prevent the secretion of thyroid receptor antibodies, which may cause either hypothyroidism or hyperthyroidism. The balance between antithyroid drugs and levothyroxine is critical in clinical practice.

Physiological Changes and Interactions Between Microbiome and the Host During Pregnancy

In recent years, it has become clear that microbiome play a variety of essential roles in human metabolism, immunity, and overall health and that the composition of these microbiome is influenced by our environment, diet, weight, hormones, and other factors. Indeed, numerous physiological and pathological conditions, including obesity and metabolic syndrome, are associated with changes in our microbiome, referred to as dysbiosis. As a result, it is not surprising that such changes occur during pregnancy, which includes substantial weight gain and significant changes in metabolism and immune defenses. The present review relates physiological changes during pregnancy to alterations in the microbial composition at various sites, including the gut, oral cavity, and vagina. Pregnancy has been linked to such microbial changes, and we believe that, in contrast to certain disease states, these microbial changes are vital for a healthy pregnancy, probably through their influence on the mother’s immunological, endocrinological, and metabolic status.

The Mysterious Universe of the TSH Receptor

The thyroid-stimulating hormone receptor (TSH-R) is predominantly expressed in the basolateral membrane of thyrocytes, where it stimulates almost every aspect of their metabolism. Several extrathyroidal locations of the receptor have been found including: the pituitary, the hypothalamus, and other areas of the central nervous system; the periorbital tissue; the skin; the kidney; the adrenal; the liver; the immune system cells; blood cells and vascular tissues; the adipose tissue; the cardiac and skeletal muscles, and the bone. Although the functionality of the receptor has been demonstrated in most of these tissues, its physiological importance is still a matter of debate. A contribution to several pathological processes is evident in some cases, as is the case of Grave's disease in its multiple presentations. Conversely, in the context of other thyroid abnormalities, the contribution of the TSH-R and its ligand is still a matter of debate. This article reviews the several different sites of expression of the TSH-R and its potential role in both physiological and pathological processes.

The efficiency and safety of methimazole and propylthiouracil in hyperthyroidism: A meta-analysis of randomized controlled trials

PURPOSE

The aim of this study was to evaluate the efficiency and safety of methimazole (MMI) and propylthiouracil (PTU) in the treatment of hyperthyroidism.

METHODS

Articles were searched through the PubMed, EMBASE, Cochrane Library, Web of Science, CNKI, Wanfang, and QVIP. The primary outcomes were clinical efficacy and thyroid hormone levels in MMI and PTU groups. The secondary outcomes were liver function indexes and adverse reactions in MMI and PTU groups. Results were expressed as weighted mean difference (WMD) or odds ratio (OR) with 95% confidence intervals (CIs). The Begg test was applied to assess the publication bias.

RESULTS

Totally, 16 randomized controlled trials were retained in this meta-analysis with 973 patients receiving MMI and 933 receiving PTU. The levels of triiodothyronine (T3) (WMD = -1.321, 95% CI: -2.271 to -0.372, P = .006), thyroxine (T4) (WMD = -37.311, 95% CI: -61.012 to -13.610, P = .002), Free T3 (FT3) (WMD = -1.388, 95% CI: -2.543 to -0.233, P = .019), Free T4 (FT4) (WMD = -3.613, 95% CI: -5.972 to -1.255, P = .003), and the risk of liver function damage (OR = 0.208, 95% CI: 0.146-0.296, P < .001) in the MMI group were lower than those in the PTU group. The thyroid-stimulating hormone level (WMD = 0.787, 95% CI: 0.380-1.194, P < .001) and the risk of hypothyroidism (OR = 2.738, 95% CI: 1.444-5.193, P = .002) were higher in the MMI group than those in the PTU group.

CONCLUSIONS

Although MMI might have higher risk of hypothyroidism than PTU, the efficacy of MMI may be better than PTU in patients with hyperthyroidism regarding reducing T3, T4, FT3, and FT4 levels, decreasing the risk of liver function damage and increasing the level of thyroid-stimulating hormone.

REGISTER NUMBER

osf.io/ds637 (https://osf.io/search/).

Thyroid dysfunction in Iranian pregnant women: a systematic review and meta-analysis

BACKGROUND

Thyroid dysfunction during pregnancy is associated with adverse outcomes for both mother and fetus. The present meta-analysis was conducted to evaluate thyroid dysfunction in Iranian pregnant women.

METHODS

We registered this review at PROSPERO (registration number: CRD42020166655). The research steps in this systematic review and meta-analysis were performed according to the MOOSE protocol, and finally, reports were provided based on the PRISMA guidelines. The literature search was performed in October 2019 using the international online databases, including Web of Science, Ovid, Science Direct, Scopus, EMBASE, PubMed/Medline, Cochrane Library, EBSCO, CINAHL, Google Scholar as well as national databases were reviewed. Data were extracted after applying the inclusion and exclusion criteria and qualitative evaluation of the studies. I2 index and Q test were used to assess differences in studies. All analyses were performed using Comprehensive Meta-Analysis Software. P-value less than 0.05 was considered statistically significant. We identified 1261 potential articles from the databases, and 426 articles remained after removing the duplicate and unrelated studies. After evaluating the full text, 52 articles were removed.

RESULTS

Finally, 19 eligible studies including 17,670 pregnant women included for meta-analysis. The prevalence of thyroid dysfunction in Iranian pregnant women was 18.10% (95%CI: 13.89-23.25). The prevalence of hypothyroidism, clinical hypothyroidism, and subclinical hypothyroidism in Iranian pregnant women was respectively estimated to be 13.01% (95%CI: 9.15-18.17), 1.35% (95%CI: 0.97-1.86) and 11.90% (95%CI: 7.40-18.57). The prevalence of hyperthyroidism, clinical hyperthyroidism, and subclinical hyperthyroidism in Iranian pregnant women was respectively estimated to be 3.31% (95%CI: 1.62-6.61), 1.06% (95%CI: 0.61-1.84) and 2.56% (95%CI: 0.90-7.05). The prevalence of anti-thyroperoxidase antibody was estimated to be 11.68% (95%CI: 7.92-16.89).

CONCLUSION

The results of this meta-analysis showed a high prevalence of thyroid disorders, especially hypothyroidism. The decision to recommend thyroid screening during pregnancy for all women is still under debate, because the positive effects of treatment on pregnancy outcomes must be ensured. On the other hand, evidence about the effect of thyroid screening and treatment of thyroid disorders on pregnancy outcomes is still insufficient. Nevertheless, a large percentage of general practitioners, obstetricians and gynecologists perform screening procedures in Iran.