Preconceptional Counseling in Women with Hyperthyroidism

Preconception evaluation of couples wishing to conceive is an important step toward a healthy pregnancy and it is especially important in people with a chronic condition or at genetic risk. The most common endocrine disorders in women at reproductive age are those involving the thyroid gland and it is well recognized that hyperthyroidism (HT), over-function of the thyroid gland, is associated with risks of maternal, fetal, and neonatal complications. The aim of this paper is to review the latest evidence regarding the components of preconception counseling in women with HT that contemplate a pregnancy. We also want to raise awareness among healthcare professionals about the importance of periconceptional counseling in improving pregnancy outcomes and avoid maternal and fetal complications related to thyroid dysfunction. In women with Graves' disease seeking pregnancy, it is essential to discuss all the treatment options along with the associated risks and benefits. Extensive prospective studies are still needed to understand the implications of current recommended strategies for the management of HT in preconception and during pregnancy.

Propylthiouracil-Induced Neonatal Goiter: An Avoidable Problem

We present a case of neonatal goiter caused by exposure to propylthiouracil (PTU) during pregnancy in this case report. The mother was treated with PTU while pregnant and had a history of Graves' illness. The baby had a neck tumor and was having breathing problems when they were first seen. A big thyroid gland was detected by a neck CT scan. This instance serves as a reminder of the significance of managing maternal thyroid problems appropriately during pregnancy as well as the requirement for careful thyroid function monitoring in newborns exposed to PTU. Given the possible hazards to the growing baby, it also calls into question whether PTU is an effective first-line treatment for maternal Graves' illness during pregnancy. This case report highlights the importance of shared decision-making with patients (by discussing different treatment options and their side effects).

Management of Hyperthyroidism during Pregnancy: A Systematic Literature Review

In pregnancy, several physiological changes affect maternal circulating thyroid hormone levels. The most common causes of hyperthyroidism in pregnancy are Graves' disease and hCG-mediated hyperthyroidism. Therefore, evaluating and managing thyroid dysfunction in women during pregnancy should ensure favorable maternal and fetal outcomes. Currently, there is no consensus regarding an optimal method to treat hyperthyroidism in pregnancy. The term "hyperthyroidism in pregnancy" was searched in the PubMed and Google Scholar databases to identify relevant articles published between 1 January 2010 and 31 December 2021. All of the resulting abstracts that met the inclusion period were evaluated. Antithyroid drugs are the main therapeutic form administered in pregnant women. Treatment initiation aims to achieve a subclinical hyperthyroidism state, and a multidisciplinary approach can facilitate this process. Other treatment options, such as radioactive iodine therapy, are contraindicated during pregnancy, and thyroidectomy should be limited to severe non-responsive thyroid dysfunction pregnant patients. In light of this events, even in the absence of guidelines certifying screening, it is recommended that all pregnant and childbearing women should be screened for thyroid conditions.

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.

Reducing Birth Defects by Decreasing the Prevalence of Maternal Chronic Diseases-Evaluated by Linked National Registration Dataset

Birth defects (BDs) are an important cause of abortion, stillbirth, and infant mortality that may cause lifelong disability. The defects can be caused by genetics, environmental exposure, or maternal chronic diseases. We conducted a study to analyze the association between maternal chronic diseases and BDs and to evaluate the effect of decreasing the prevalence of maternal chronic diseases on reducing BDs. The data of newborns and their mothers were concatenated and analyzed from three national population databases: the National Health Insurance Research Database, the Birth Certificate Application, and the Birth Registration Database in Taiwan during the period of 2005 to 2014. Codes 740-759 of the International Classification of Diseases 9th Revision—Clinical Modification (ICD-9-CM) were used as the diagnosis of BDs. The prevalence of BDs was 2.72%. Mothers with cardiovascular diseases, hypertension, anemia, genitourinary tract infections, renal diseases, neurotic or psychotic disorders, gestational diabetes mellitus (DM), and pregestational type 1 or type 2 DM had a significantly higher prevalence of BDs. The population attributable risk percent (PAR%) of BDs was 1.63%, 0.55%, 0.18%, 1.06%, 0.45%, 0.22%, 0.48%, and 0.24% for maternal hypertension, cardiovascular disease, renal disease, genitourinary infection, anemia, neurotic and psychotic disorders, gestational DM, and pregestational type 1 or type 2 DM, respectively. The percentage change (−1%, −5%, and −10% of prevalence in 2034 compared with the prevalence in 2005−2014) of maternal disease and the predicted number of live births was used to estimate the decrease in the number of newly diagnosed BDs in 2034. By using the middle-estimated number of live births in 2034, we predicted that the number of BDs would decrease by 302, 102, 33, 196, 83, 41, 89, and 44 with a −5% prevalence of maternal hypertension, cardiovascular disease, renal disease, genitourinary infection, anemia, neurotic and psychotic disorders, gestational DM, and pregestational type 1 or type 2 DM, respectively. We conclude that mothers with chronic diseases, including cardiovascular diseases, hypertension, anemia, genitourinary tract infections, renal diseases, neurotic or psychotic disorders, gestational DM, and pregestational type 1 or type 2 DM, have a significantly higher (p < 0.01) prevalence of having offspring with BDs. Mothers with chronic diseases are associated with BDs. It is very important to set up a policy to decrease the prevalence of these maternal chronic diseases; then, we can reduce the incidence of BDs.

Medication use during pregnancy and birth defects in Hunan province, China, during 2016-2019: A cross-sectional study

Safety of drug use during pregnancy attracts attentions from clinicians, pregnant woman, and even the total society. However, the studies about medication use during pregnancy and the followed birth defects (BDs) are rare in Chinese. To study condition about medication use during pregnancy and the followed BDs in Hunan province of China, here a cross-sectional study was carried out. All women using medication during pregnancy and delivering fetuses with BDs in Hunan province, China, during 2016 to 2019 were employed in this study. The descriptive analysis was carried out with Excel 2010, and the data analyses were performed by using Chi-Squared test in SPSS 16.0. After filtering, a total of 752 cases were included. In these fetuses, the males are more than females (P < .05). The severe BDs, leading to death or uncorrectable lifelong deformity, were observed for 346 times, and the other (minor) BDs were observed for 593 times. The most used drugs, categorized into pregnancy C, D, or X degrees by food and drug administration (FDA) or pharmaceutical manufacturers, mainly included anti-hyperthyroidism drugs, anti-epilepsy drugs, preventing miscarriage drugs, etc. This population-based data highlight the potential high risks for BDs from the aspect of drug use during pregnancy in Hunan province of China, and drugs with more safety, less kinds, and lower doses should be the better choice for pregnant women.

Antithyroid drug therapy in pregnancy and risk of congenital anomalies: Systematic review and meta-analysis

OBJECTIVES

The risk of congenital anomalies following in utero exposure to thionamide antithyroid drugs (ATDs) is unresolved. Observational studies are contradictory and existing meta-analyses predate and preclude more recent studies. We undertook an updated meta-analysis of congenital anomaly risk in women exposed to carbimazole or methimazole (CMZ/MMI), propylthiouracil (PTU), or untreated hyperthyroidism in pregnancy.

METHODS

We searched Medline, Embase, and the Cochrane database for articles published up till August 2021. We pooled separate crude and adjusted risk estimates using random effects models and subgroup analyses to address heterogeneity.

RESULTS

We identified 16 cohort studies comprising 5957, 15,785, and 15,666 exposures to CMZ/MMI, PTU, and untreated hyperthyroidism, respectively. Compared to nondisease controls, adjusted risk ratio (RR) and 95% confidence intervals (95% CIs) for congenital anomalies was increased for CMZ/MMI (RR, 1.28; 95% CI, 1.06-1.54) and PTU (RR, 1.16; 95% CI, 1.08-1.25). Crude risk for CMZ/MMI was increased relative to PTU (RR, 1.20; 95% CI, 1.01-1.43). Increased risk was also seen with exposure to both CMZ/MMI and PTU, that is, women who switched ATDs in pregnancy (RR, 1.51; 95% CI, 1.14-1.99). However, the timing of ATD switch was highly variable and included prepregnancy switches in some studies. The excess number of anomalies per 1000 live births was 17.2 for patients exposed to CMZ/MMI, 9.8, for PTU exposure, and 31.4 for exposure to both CMZ/MMI and PTU. Risk in the untreated group did not differ from control or ATD groups. The untreated group was however highly heterogeneous in terms of thyroid status. Subgroup analysis showed more positive associations in studies with >500 exposures and up to 1-year follow-up.

CONCLUSIONS

ATD therapy carries a small risk of congenital anomalies which is higher for CMZ/MMI than for PTU and does not appear to be reduced by switching ATDs in pregnancy. Due to key limitations in the available data, further studies will be required to clarify the risks associated with untreated hyperthyroidism and with switching ATDs in pregnancy.

Safety of Japanese herbal Kampo medicines for the treatment of depression during pregnancy

OBJECTIVE

To clarify the fetal safety of herbal Kampo medicines, including Hange-koboku-to, Koso-san, Nyoshin-san, Yokukansan, Yokukansan-kachinpi-hange, Saiko-keishikankyo-to, Keishi-karyukotu-borei-to, and Kanbaku-taisou-to, when administered to pregnant women with depression using a large healthcare administrative database.

METHODS

We extracted data from the JMDC Claims Database (2005-2018) for this retrospective cohort study of pregnant women aged 19 years or older admitted to obstetric clinics or hospitals for delivery. Participants were classified into four groups: those without depression, those diagnosed with depression without medication, those given Kampo medicines for depression, and those given western medicines for depression. Neonatal outcomes (congenital anomalies, low birth weight, and preterm birth) were considered as the safety outcome measures.

RESULTS

We identified 179 707 eligible mothers. The adverse outcomes did not differ significantly between participants receiving Kampo medicine and those not diagnosed with depression during pregnancy. The proportion of low-birth-weight neonates did not differ significantly between the Kampo medicine and non-depression groups (adjusted odds ratio [aOR] 1.28; 95% confidence interval [CI] 0.86-1.91), but was significantly higher in the unmedicated depression group (aOR 1.31; 95% CI 1.07-1.61) and western medicine group (aOR 1.47; 95% CI 1.18-1.83).

CONCLUSION

Kampo medicines are safe for treating depression during pregnancy without increasing the incidence of congenital anomalies, low birth weight, or preterm birth.

Efficacy of propylthiouracil in the treatment of pregnancy with hyperthyroidism and its effect on pregnancy outcomes: A meta-analysis

Background

Hyperthyroidism affects about 0.2%-2.7% of all pregnancies, and is generally treated with propylthiouracil (PTU). However, previous studies about the effects of propylthiouracil on maternal or foetal are contentious.

Objective

This meta-analysis was carried out to investigate the safety and efficacy of propylthiouracil during pregnancy.

Materials and methods

PubMed, EBSCO, Embase, Scopus, Web of Science, Cochrane, CNKI, Wanfang and VIP database were searched from inception until August 31, 2021 for all available randomized controlled trials (RCTs) or cohort studies that evaluated the efficacy of propylthiouracil and its effects on pregnancy outcomes. Odds ratio (OR) and 95% confidence interval (CI) were used for binary variables, weighted mean difference (WMD) and 95% confidence interval (CI) were used for continuous variables. RevMan5.4 and Stata 16.0 were used for performing the meta-analysis.

Results

The researchers examined data from 13 randomized controlled trials and cohort studies involving 18948 infants. Congenital anomalies were not significantly associated with PTU in the pooled results (OR = 1.03, 95%CI: 0.84–1.25, P = 0.80, I² = 40.3%). There were no statistically significant differences in neonatal hypothyroidism (OR = 0.55, 95%CI: 0.06–4.92, P = 0.593, I² = 57.0%) or hepatotoxicity (OR = 0.34, 95%CI: 0.08–1.48, P = 0.151, I² = 0.0%) exposed to PTU compared to the control group. The serum levels of FT3, FT4, TT3, and TT4 were significantly lower in the propylthiouracil group compared to the control group.

Conclusion

This meta-analysis confirmed the beneficial effects of propylthiouracil treatment, namely the risks of adverse pregnancy outcomes were not increased, and it also proved PTU’s efficacy in the treatment of pregnant women with hyperthyroidism. The findings supported the use of propylthiouracil during pregnancy with hyperthyroidism in order to improve clinical pregnancy outcomes in patients with thyroid dysfunction.

MANAGEMENT OF THYROTOXICOSIS AND PREGNANCY: Review of the current literature and an update of the care pathway

Pregnancy can be complicated by hyperthyroidism or thyrotoxicosis. Diagnosis is founded on an increase in free thyroid hormones and low TSH. The most frequent etiologies are Graves' disease, an autoimmune disease linked to stimulatory anti-TSH receptor antibodies, and non-autoimmune gestational hyperthyroidism linked to the TSH-like activity of the chorionic growth hormone (hCG). During pregnancy, thyrotoxicosis can entail maternal, obstetrical and fetal or neonatal complications. Graves' hyperthyroidism may be responsible for fetal and neonatal hyperthyroidism due to placental transfer of stimulatory anti-TSH receptor antibodies. During pregnancy, treatment of thyrotoxicosis must restore normal thyroid function in the mother without affecting fetal thyroid function. The recent reassessment of the prevalence of teratogenic effects in children of women treated with antithyroid drugs in the first weeks of gestation should orient the care pathway before and during pregnancy for women of child-bearing age with hyperthyroidism linked to Graves' disease.

Pregnancy Outcomes among Women with Graves' Hyperthyroidism: A Retrospective Cohort Study

OBJECTIVE

The primary objectives of this study are to compare the rates of preterm birth; fetal growth restriction and low birth weight between the following groups: (1) pregnant women treated for thyrotoxicosis and low-risk pregnancies; (2) between pregnant women with thyrotoxicosis with no need of medication and low-risk pregnancies; and (3) between those treated with MMI and PTU.

METHODS

The medical records of singleton pregnancies with thyrotoxicosis were comprehensively reviewed. Low-risk pregnancies matched for age and parity were randomly recruited as controls. The obstetric outcomes were compared between both groups; the outcomes of various subgroups of the thyrotoxicosis group were also compared.

RESULTS

A total of 408 pregnant women with thyrotoxicosis were recruited. Compared with the controls; the women of the thyrotoxicosis group had significantly higher rates of low birth weight (LBW) (23.7% vs. 17.7%; p: 0.036), preterm birth (19.3% vs. 12.3%; p: 0.007), preeclampsia (8.5% vs. 4.4%; p: 0.019) and cesarean section (21.5% vs. 16.0%; p: 0.046). In the thyrotoxicosis group; 67; 127; and 158 patients were treated with MMI; PTU and no anti-thyroid drug (ATD), respectively. All obstetric outcomes were comparable between the women treated with PTU and those with MMI; and between the controlled and uncontrolled groups. However, women who needed ATD had significantly higher rates of LBW and preterm birth than those without medications.

CONCLUSIONS

Thyrotoxicosis, whether treated or not needing ATDs, was significantly associated with an increased risk of adverse pregnancy outcomes. Also, active disease, indicated by the need for ATD significantly increased the risk of such adverse outcomes; whereas the patients treated with MMI or PTU had comparable adverse outcomes.

Antithyroid drug use during pregnancy and the risk of birth defects in offspring: systematic review and meta-analysis of observational studies with methodological considerations

AIMS

Maternal antithyroid drug (ATD) use during pregnancy has been associated with an increased risk of birth defects in offspring. Uncertainty remains on the size of this risk and how it compares to untreated hyperthyroidism due to methodological limitations of previous studies.

METHODS

Systematic review of MEDLINE and EMBASE identifying observational studies examining ATD use during pregnancy and risk of birth defects by 28 August 2020. Data were extracted on study characteristics, effect estimates and comparator groups. Adjusted effect estimates were pooled using a random-effects generic inverse variance method and absolute risk calculated.

RESULTS

Seven cohort studies and 1 case-control study involving 6 212 322 pregnancies and 388 976 birth defects were identified reporting regression effect estimates. Compared to an unexposed population comparison, the association between ATD use during pregnancy and birth defects in offspring was: adjusted risk ratio (aRR) 1.16 95% confidence interval (CI) 1.08-1.25 for propylthiouracil (PTU); aRR 1.28 95%CI 1.06-1.54 for methimazole/carbimazole (MMI/CMZ); aRR 1.51, 95%CI 1.16-1.97 for both MMI/CMZ and PTU; and aRR 1.15 95%CI 1.02-1.29 for untreated hyperthyroidism. The excess risk of any and major birth defects per 1000, respectively, was: 10.2 and 1.3 for PTU; 17.8 and 2.3 for MMI/CMZ; 32.5 and 4.1 for both MMI/CMZ and PTU; and 9.6 and 1.2 for untreated hyperthyroidism.

CONCLUSIONS

When appropriately analysed the risk of birth defects associated with ATD use in pregnancy is attenuated. Although still elevated, the risk of birth defects is smallest with PTU compared to MMI/CMZ and may be similar to that of untreated hyperthyroidism.

Exposure to Propylthiouracil in the First Trimester of Pregnancy and Birth Defects: A Study at a Single Institution

Context

Medical treatment of Graves disease during the first trimester has been the subject of controversy ever since treatment with an antithyroid drug during the first trimester was reported to possibly be associated with an increased risk of birth defects in newborns.

Objective

We investigated whether the incidence of birth defects among newborns born to mothers with Graves disease (GD) treated with propylthiouracil (PTU) during the first trimester of pregnancy was higher than in a control group that was not exposed to any medication.

Methods

We reviewed the cases of 1913 women with GD who gave birth between January 1, 2015, and May 31, 2019. Detailed information concerning the outcome of pregnancy and the presence of birth defects was collected at the first visit after the delivery and again 1 year after delivery. We classified the mothers and infants into 3 groups according to the treatment the mother had received for GD in the first trimester of pregnancy: a group in which the mothers had been treated with PTU alone (PTU group), a group in which the mothers had not been treated with any medication (control group), and a group in which the mothers had received some other medical treatment, such as thiamazole, potassium iodide, or 2 or more drugs (other treatment group).

Results

The incidence of malformed infant births was 5.5% (30/541 infants) in the PTU group and 5.7% (27/ 475 infants) in the control group. There were no specific birth defects in the PTU group, and there were no significant differences between PTU dosages or maternal thyroid function according to whether mothers had delivered a child with a birth defect.

Conclusion

The results of our retrospective study showed that treatment with PTU during the first trimester of pregnancy did not increase the incidence of birth defects among newborns.

Teratogen update: Antithyroid medications

OBJECTIVE

Thyroid disorders including hyperthyroidism are common during pregnancy. Untreated hyperthyroidism can result in adverse outcomes for pregnancy.

METHODS

Iodine, propylthiouracil (PTU), carbimazole (CMZ), and methimazole (MMI) are common medications for hyperthyroidism treatment. The literature regarding antithyroid medication use in pregnancy and breastfeeding is reviewed.

RESULTS

Animal studies for PTU have suggested congenital anomalies while animal studies for MMI have only indicated adverse outcomes at higher doses than used in humans. Epidemiological studies have noted an increased risk of congenital anomalies for PTU less often than CMZ or MMI but the epidemiological evidence remains mixed. A pattern of anomalies has been described for CMZ and MMI, from both case and epidemiological studies, including choanal atresia, aplasia cutis congenita, and other facial, heart, gastrointestinal, and skin anomalies. Closer examination of cases indicates that a few cases of the anomalies have occurred without exposure to CMZ or MMI and outside of the proposed critical period. PTU has a small risk of hepatotoxicity which rarely results in liver transplantation and death. Some authors have suggested that PTU be prescribed in early pregnancy and switched to MMI in late pregnancy. Untreated hyperthyroidism, from either a lack of medications or switching medications during the first trimester, may also increase the chance of congenital anomalies. Multiple case studies and larger epidemiological studies have failed to provide clear, consistent outcomes for the use of PTU, CMZ, and MMI in pregnancy. MMI and PTU both enter the breastmilk in small amounts.

CONCLUSION

Additional research is needed to assist in the medical management and exposure counseling of pregnant and breastfeeding women with hyperthyroidism.

Management of thyrotoxicosis during pregnancy

Thyrotoxicosis during pregnancy should be adequately managed and controlled to prevent maternal and fetal complications. The evaluation of thyroid function in pregnant women is challenged by the physiological adaptations associated with pregnancy, and the treatment with antithyroid drugs (ATD) raises concerns for the pregnant woman and the fetus. Thyrotoxicosis in pregnant women is mainly of autoimmune origin, and the measurement of thyroid stimulating hormone-receptor antibodies (TRAb) plays a key role. TRAb helps to distinguish the hyperthyroidism of Graves' disease from gestational hyperthyroidism in early pregnancy, and to evaluate the risk of fetal and neonatal hyperthyroidism in late pregnancy. Furthermore, the measurement of TRAb in early pregnancy is recommended to evaluate the need for ATD during the teratogenic period of pregnancy. Observational studies have raised concern about the risk of birth defects associated with the use of ATD in early pregnancy and challenged the clinical management and choice of treatment.

Antithyroid drugs and birth defects

Antithyroid drugs (ATDs) are preferred for the treatment of hyperthyroidism caused by Graves’ disease in pregnant women. The drugs have been a recognized treatment for decades, and a general risk of side effects is known. For the use of ATDs in pregnancy, a concern about teratogenic side effects has been brought forward since the 1970s. In more recent years, a number of large observational studies have added new evidence and quantified the risk of birth defects associated with different types of ATDs. The findings that both Methimazole (MMI) and Propylthiouracil (PTU) are associated with birth defects have challenged the clinical recommendations on the treatment of hyperthyroidism in pregnancy, and certain aspects remain unclarified. In this review, the current evidence on the risk of birth defects associated with the use of ATDs in early pregnancy is described, and determinants of causality are discussed. This includes the current evidence of a biological gradient and the role of maternal thyroid function per se. Finally, clinical aspects of the timing and type of treatment is discussed, and future perspectives are addressed. Current evidence corroborates a risk of birth defects associated with MMI while more evidence is needed to determine the teratogenic potential of PTU. Detailed assessment of type and timing of exposure in large cohorts are needed. Moreover, studies investigating alternative or new treatments are warranted.

Safety of antithyroid drugs in pregnancy: update and therapy implications

Introduction: The thionamide antithyroid drugs, methimazole (MMI), its pro-drug derivative carbimazole (CMZ), and propylthiouracil (PTU) are the mainstay of treatment for hyperthyroidism in pregnancy. However, antithyroid drugs carry risks of adverse effects that can affect fetal and maternal well-being.Areas covered: This review provides an update on the safety of antithyroid drugs in pregnancy, focusing on the most serious concerns of severe liver disease and congenital anomalies.Expert opinion: PTU-induced liver disease is uncommon but can run a catastrophic course in pregnancy with a risk of liver failure and threats to maternal or fetal survival. Acute pancreatitis is a relatively rare occurrence that has been linked to thionamide use in a handful of reports in non-pregnant individuals. Observational studies on the risk of birth defects with antithyroid drug exposure in pregnancy overall show an increase in birth defect risk with exposure to CMZ/MMI, and to a lesser extent, PTU. Further studies are required to determine whether the currently recommended approach of switching between thionamide drugs in pregnancy improves outcomes. Ultimately, a preventative strategy of offering definitive therapy to hyperthyroid women of childbearing potential offers the best approach to truly reduce the risks of antithyroid drug adverse effects in pregnancy.

Treatment of Graves' hyperthyroidism with thionamides: a position paper on indications and safety in pregnancy

CONTEXT

Graves' disease affects 3% of women and 0.5% of men in the general population. The first line treatment of Graves' hyperthyroidism is based on the administration of antithyroid drugs (ATD), propylthiouracil (PTU), methimazole (MMI) and carbimazole. A recent warning from the Italian Drug Agency (Agenzia Italiana del Farmaco AIFA) reported the risk of MMI-induced acute pancreatitis. In addition, AIFA highlighted the possible association of MMI treatment during the first trimester of pregnancy with congenital malformations, thus recommending the use of effective contraceptive methods in women of childbearing age treated with MMI.

METHODS AND RESULTS

Revision of literature reported less than ten cases of the alleged MMI pancreatitis, allowing the inclusion of MMI in class III drug regarding the relative risk for drug-induced pancreatitis. Data available on the effect of hyperthyroidism per se on the risk of fetal malformations, although scanty, are sufficient to recommend treatment with ATD of the hyperthyroid pregnant woman. Case reports and population studies either suggesting or not suggesting MMI-induced fetal malformations do not allow unquestionable conclusions on this matter.

CONCLUSIONS

This consensus by experts from Italian Endocrine and Gynecologic Scientific Societies has edited recommendations derived form the available data and published guidelines of International Scientific Societies.

Maternal Thyroid Function, Use of Antithyroid Drugs in Early Pregnancy, and Birth Defects

CONTEXT

Antithyroid drug (ATD) therapy in early pregnancy is associated with birth defects, but more data are needed to substantiate the risk associated with different types of ATD. Furthermore, the role of abnormal maternal thyroid function per se remains unclarified.

OBJECTIVE

To evaluate the risk of birth defects associated with the use of ATD in an extended nationwide cohort and the role of abnormal maternal thyroid function in birth cohorts including stored maternal blood samples from early pregnancy.

PARTICIPANTS

Danish pregnant women and their live-born children, including 1,243,353 children from a Nationwide Register-Based Cohort (NRBC), 1997 to 2016; 8830 children from the Danish National Birth Cohort (DNBC), 1997 to 2003; and 14,483 children from the North Denmark Region Pregnancy Cohort (NDRPC), 2011 to 2015.

MAIN OUTCOME MEASURES

Birth defects diagnosed before 2 years of age.

RESULTS

In the NRBC, altogether 2718 (0.2%) children had been exposed to ATD in early pregnancy. The overall frequency of birth defects was 6.7% (95% CI, 6.7% to 6.8%) in nonexposed children and higher after exposure to methimazole/carbimazole (9.6%; 95% CI, 8.2% to 11.2%) and propylthiouracil (8.3%; 95% CI, 6.7% to 10.3%). On the other hand, the frequency of maternal thyroid dysfunction in early pregnancy was similar in the random cohort and in cases of birth defect in the DNBC (12.4 vs 12.6%, P = 0.8) and the NDRPC (15.1 vs 15.4%, P = 0.8).

CONCLUSIONS

Results corroborate an increased risk of birth defects associated with the use of ATD in early pregnancy and suggest that abnormal maternal thyroid function is not a major risk factor for birth defects.

Birth defects in Taiwan: A 10-year nationwide population-based, cohort study

BACKGROUND/PURPOSE

Birth defects (BDs) are main causes of mortality and disability in infants and children. The aims of this study were to analyze the prevalence, types and risk factors of BDs in Taiwan.

METHODS

Data of all births (including live and stillbirths), types, characteristics, and associated risk factors of BDs were obtained from the National Birth Registry and National Health Insurance Research Data base in Taiwan between 2005 and 2014. Birth defects were coded according to International Classification of Diseases 9th Revision-Clinical Modification codes 740-759.

RESULTS

A total of 55,299 infants were diagnosed as having BDs among 2,033,004 births. The prevalence of BDs was 271.66 per 10,000 births. The prevalence of BDs did not change significantly between 2005 and 2014, there was a higher birth rate and lower BDs in 2012 (year of dragon) in Taiwan. The most common type of BDs was cardiovascular abnormalities, and ventricular septal defect was the most common disease. Extreme maternal age (<18 years or ≧30 years), preterm, and low birth weight were associated with BDs. Maternal diseases associated with BDs included hypertension, cardiovascular diseases, renal diseases, genitourinary infections, anemia, mental disorders, and diabetes mellitus.

CONCLUSION

The prevalence of BDs was 271.66 per 10,000 births. The most common types of BDs were cardiovascular abnormalities. If we can reduce maternal chronic diseases, we will decrease the prevalence of BDs.

Medications that Cause Fetal Anomalies and Possible Prevention Strategies

Many conditions that require frequent medication use are common during pregnancy. The purpose of this article is to list some of the most common of these disorders and to discuss the risk to the developing fetus of the medications used most frequently to treat them. Included are drugs used for the treatment of asthma, nausea and vomiting, hyperthyroidism, pain and fever, and depression during pregnancy.

Central congenital hypothyroidism caused by maternal thyrotoxicosis

Central congenital hypothyroidism (CCH) is a rare and underdiagnosed disease that sometimes is caused by maternal Graves' disease. We report a case of CCH caused by undiagnosed, initially antibody-negative maternal thyrotoxicosis with possible disruption of fetal hypothalamic-pituitary-thyroid axis maturation. In CCH, maternal thyroid disease should be considered.

Additive effect of congenital heart disease and early developmental disorders on attention-deficit/hyperactivity disorder and autism spectrum disorder: a nationwide population-based longitudinal study

In this retrospective nationwide population-based case-control study, we investigated the impact of congenital heart disease (CHD) on the development of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), which remains unclear. Children aged <18 years that were diagnosed with CHD (n = 3552) between January 1, 1997 and December 31, 2009 were identified from the National Health Insurance Research Database in Taiwan. Non-CHD controls (n = 14,208) matched for age and sex (1:4) were selected from the same dataset. All subjects were observed until December 31, 2011 or their death. Comorbid perinatal conditions and early developmental disorders (EDD) that were diagnosed before ADHD and ASD diagnosis were also analyzed. The incidence rates of perinatal comorbidities, EDD, ADHD, and ASD were higher in the CHD group than in the control group. Multivariate Cox regression analysis revealed that the CHD group had an increased risk of developing ADHD (adjusted hazard ratio [aHR] 2.52, 95% confidence interval CI 1.96-3.25) and ASD (aHR 1.97, 95% CI 1.11-3.52) after adjusting for confounding comorbidities. EDD, but not perinatal comorbidities were also independent risk factors for ADHD and ASD after adjustment. Subgroup analysis indicated that the risk for ADHD (HR 16.59, 95% CI 12.17-22.60) and ASD (HR 80.68, 95% CI 39.96-176.12) was greatly increased in CHD subjects with EDD than in non-CHD subjects without EDD. These findings suggested that CHD at birth and EDD during early childhood were two independent risk factors for ADHD and ASD and that concurrent CHD and EDD might additively increase these risks.

Risk of embryopathies with use of antithyroidal medications

PURPOSE OF REVIEW

Hyperthyroidism in pregnant women should be adequately treated to prevent maternal and fetal complications. The treatment of choice in pregnancy is antithyroidal medications (ATDs). The risk of embryopathies associated with the use of Methimazole (MMI) and Propylthiouracil (PTU) in early pregnancy is a matter of clinical attention and concern. This review describes current evidence and how scientific findings are reflected in current clinical guidelines.

RECENT FINDINGS

Embryopathies after the use of ATDs were previously mainly described in case reports and considered rare. Recent large observational studies, including nonexposed control groups, have quantified an increased risk of embryopathies associated with use of ATDs during pregnancy. Findings suggest a risk of embryopathies with the use of both MMI and PTU, but the pattern of embryopathies differs, and embryopathies with the use of PTU appear less severe.

SUMMARY

Current guidelines highlight the need for clinical attention on the use of ATDs in early pregnancy. Patients managed on ATDs for the treatment of hyperthyroidism should be counseled to report a pregnancy as early as possible. PTU is the recommended treatment in early pregnancy, but if the risk of relapse or worsening of hyperthyroidism is considered low, it is suggested that ATD treatment can be withdrawn followed by frequent monitoring of thyroid function.

Birth defects after use of antithyroid drugs in early pregnancy: a Swedish nationwide study

OBJECTIVE

Antithyroid drugs (ATDs) may have teratogenic effects, but more evidence is needed on the risk and types of birth defects after the use of methimazole (MMI) and propylthiouracil (PTU). This study aimed to evaluate the association between the use of ATDs in early pregnancy and birth defects.

DESIGN

Swedish nationwide register-based cohort study.

METHODS

The study included 684 340 children live-born in Sweden from 2006 to 2012. Exposure groups defined by maternal ATD use in early pregnancy were MMI (n = 162); PTU (n = 218); MMI and PTU (n = 66); ATD before or after, but not in pregnancy (n = 1551) and non-exposed (never ATD (n = 682 343)). Outcome was cumulative incidence of birth defects diagnosed before two years of age.

RESULTS

The cumulative incidence of birth defects was not significantly different in children exposed to MMI (6.8%, P = 0.6) or PTU (6.4%, P = 0.4) vs non-exposed (8.0%). For subtypes of birth defects, MMI was associated with an increased incidence of septal heart defects (P = 0.02). PTU was associated with ear (P = 0.005) and obstructive urinary system malformations (P = 0.006). A case of choanal atresia was observed after exposure to both MMI and PTU. The incidence of birth defects in children born to mothers who received ATD before or after, but not in pregnancy, was 8.8% and not significantly different from non-exposed (P = 0.3), MMI exposed (P = 0.4) or PTU exposed (P = 0.2).

CONCLUSIONS

MMI and PTU were associated with subtypes of birth defects previously reported, but the frequency of ATD exposure in early pregnancy was low and severe malformations described in the MMI embryopathy were rarely observed.

Effects of methimazole and propylthiouracil exposure during pregnancy on the risk of neonatal congenital malformations: A meta-analysis

Objective

The aim of this study was to determine the effect of exposure to different antithyroid drugs during pregnancy on the incidence of neonatal congenital malformations.

Methods

A meta-analysis was performed to compare the incidence of neonatal congenital malformations after exposure to different antithyroid drugs during pregnancy. Twelve studies that met the inclusion criteria were included in this meta-analysis. PubMed, Embase, and CENTRAL databases were searched from inception until January 2017. Study designs included case–control studies, prospective cohort studies, and retrospective cohort studies.

Results

Twelve studies involving 8028 participants with exposure to different antithyroid drugs during pregnancy were included in this study; however, only 10 studies involving 5059 participants involved exposure to different antithyroid drugs exactly during pregnancy. Our results indicated that exposure to methimazole (MMI)/carbimazole (CMZ) only during pregnancy significantly increased the risk of neonatal congenital malformations compared to no antithyroid drug exposure (OR 1.88; 95%CI 1.33 to 2.65; P = 0.0004). No differences were observed between propylthiouracil (PTU) exposure and no antithyroid drug exposure only during pregnancy (OR 0.81; 95%CI 0.58 to 1.15; P = 0.24). Exposure to MMI/CMZ only during pregnancy significantly increased the risk of neonatal congenital malformations compared to that associated with exposure to PTU (OR 1.90; 95%CI 1.30 to 2.78; P = 0.001).

Conclusion

For pregnant women with hyperthyroidism, exposure to MMI/CMZ significantly increased the incidence of neonatal congenital malformations compared to exposure to PTU and no antithyroid drug exposure; however, no differences were observed between PTU exposure and no antithyroid drug exposure.

Antithyroid drug therapy in pregnancy: a review of guideline recommendations

The antithyroid drugs, Carbimazole, Methimazole, and Propylthiouracil remain the mainstay of Graves' disease management in pregnancy. A series of Clinical Practice Guidelines aimed at optimising fetal and maternal outcomes in women with Graves' disease have been published in recent years. Areas covered: This review examines existing guideline recommendations on antithyroid drug management of Graves' disease in pregnancy. Expert commentary: Recent guidelines have been shaped by expanding knowledge of the adverse effect profiles of antithyroid drugs on the developing fetus. A core management strategy is to limit fetal exposure to excess thyroid hormones and to curtail adverse drug effects through effective preconception and peri-conception management. Propylthiouracil is the recommended treatment in the first trimester of pregnancy but there is uncertainty regarding antithyroid drug choices in women who continue to require treatment in later pregnancy. Further studies are needed to fully evaluate the risks of congenital anomalies following intrauterine thionamide exposure.

Current challenges in the pharmacological management of thyroid dysfunction in pregnancy

INTRODUCTION

Thyroid dysfunction is common in pregnancy and has adverse fetal and maternal health consequences. A number of challenges in the management of gestational thyroid dysfunction remain unresolved including uncertainties in optimal thresholds for correction of hypothyroidism and strategies for pharmacological management of hyperthyroidism. Areas covered: We addressed key challenges and areas of uncertainty in the management of thyroid dysfunction in pregnancy. Expert commentary: Gestational thyroid hormone reference intervals vary according to population ethnicity, iodine nutrition, and assay method and each population should derive trimester specific reference intervals for use in pregnancy. Subclinical hypothyroidism and isolated hypothyroxinaemia are common in pregnancy but there is no consensus on the benefits of correcting these conditions. Although observational studies show potential benefits of levothyroxine on child neurocognitive function these benefits are have not been supported by two controlled trials. Carbimazole should be avoided in the first trimester of pregnancy due to risk of congenital anomalies but recent studies would suggest that this risk is present to a lesser magnitude with propylthiouracil. Current international guidelines recommend the use of propylthiouracil in the first trimester and switching to carbimazole for the remainder of pregnancy but the benefits and practicalities of this approach is unproven.

ENDOCRINOLOGY IN PREGNANCY: Pregnancy and the incidence, diagnosing and therapy of Graves' disease

Thyroid hormones are essential developmental factors, and Graves' disease (GD) may severely complicate a pregnancy. This review describes how pregnancy changes the risk of developing GD, how early pregnancy by several mechanisms leads to considerable changes in the results of the thyroid function tests used to diagnose hyperthyroidism, and how these changes may complicate the diagnosing of GD. Standard therapy of GD in pregnancy is anti-thyroid drugs. However, new studies have shown considerable risk of birth defects if these drugs are used in specific weeks of early pregnancy, and this should be taken into consideration when planning therapy and control of women who may in the future become pregnant. Early pregnancy is a period of major focus in GD, where pregnancy should be diagnosed as soon as possible, and where important and instant change in therapy may be warranted. Such change may be an immediate stop of anti-thyroid drug therapy in patients with a low risk of rapid relapse of hyperthyroidism, or it may be an immediate shift from methimazole/carbimazole (with risk of severe birth defects) to propylthiouracil (with less risk), or maybe to other types of therapy where no risk of birth defects have been observed. In the second half of pregnancy, an important concern is that not only the mother with GD but also her foetus should have normal thyroid function.

Graves' Disease Pharmacotherapy in Women of Reproductive Age

Graves' disease is an autoimmune disorder in which inappropriate stimulation of the thyroid gland results in unregulated secretion of thyroid hormones resulting in hyperthyroidism. Graves' disease is the most common cause of autoimmune hyperthyroidism during pregnancy. Treatment options for Graves' disease include thioamide therapy, partial or total thyroidectomy, and radioactive iodine. In this article, we review guideline recommendations for Graves' disease treatment in women of reproductive age including the recent guideline from the American College of Obstetricians and Gynecologists. Controversy regarding appropriate thioamide therapy before, during, and after pregnancy is reviewed. Surgical and radioactive iodine therapy considerations in this patient population are also reviewed. In patients who may find themselves pregnant during therapy or develop Graves' disease during their pregnancy, consideration should be given to the most appropriate treatment course for the mother and fetus. Thioamide therapy should be used with either propylthiouracil or methimazole at appropriate doses that target the upper range of normal to slightly hyperthyroid to avoid creating hypothyroidism in the fetus. Consideration should also be given to the adverse effects of thioamide, such as agranulocytosis and hepatotoxicity, with appropriate patient consultation regarding signs and symptoms. Individuals who wish to breastfeed their infants while taking thioamide should receive the lowest effective dose. Surgery should be reserved for extreme cases and limited to the second trimester, if possible. Radioactive iodine therapy may be used in nonpregnant individuals, with limited harm to future fertility. Radioactive iodine therapy should be withheld in pregnant women and those who are actively breastfeeding. Clinicians should keep abreast of developments in clinical trials and evidence-based recommendations regarding Graves' disease in reproductive-age women for any changes in evidence-based practice.

Pregnancy outcomes after fetal exposure to antithyroid medications or levothyroxine

AIM

To investigate whether fetal exposure to antithyroid drugs (ATD) and levothyroxine affects gestational age (GA), birth weight, birth length, head circumference and prevalence of congenital anomalies.

METHODS

Cohort of all pregnancies from GA 12 weeks recorded in Danish registries from 1995-2010. Exposure was having a prescription for ATD or levothyroxine from 91 days before to 91 days after pregnancy start (n=8318). The reference group was pregnant women without exposure of ATD or levothyroxine (n=969303). A subpopulation was linked to the Danish EUROCAT congenital anomaly register.

RESULTS

Overall 0.66% of the pregnant women had a prescription for levothyroxine and 0.19% had a prescription for ATD during the exposure period. There was no difference in proportion of live births compared to non-exposed pregnancies, but infants exposed to ATD were more often born very preterm (1.99% versus 0.94% Odds Ratio 2.04, 95% CI 1.46 - 2.86) and had higher infant mortality (Odds ratio 2.37, 95% CI 1.42 - 3.94). Infants exposed to ATD were more likely to have low birth weight and length for GA (Odds ratios 1.29 (1.12 - 1.50) and 1.40 (1.17 - 1.66). There was no difference in head circumference for the 3 exposure groups. Prevalence of congenital anomalies was the same for exposed and non-exposed pregnancies.

CONCLUSION

Fetal exposure to ATD resulted in lower GA, birth weight, length and higher infant mortality. Treatment for hypothyroidism had no significant impact on these variables. There was no difference in prevalence of congenital anomalies.

Current trends in antithyroid drug treatment of Graves' disease

INTRODUCTION

Graves' hyperthyroidism is associated with significant morbidity and mortality risk. The thionamides, methimazole, its pro-drug derivative carbimazole, and propylthiouracil, remain a cornerstone of management. Yet despite decades of use, optimal strategies for maximising treatment response and curtailing adverse effect risk remains uncertain.

AREAS COVERED

We reviewed the current literature on the evidence based medical management of Graves' disease. Specifically, we evaluated current approaches to the use of thionamides, adjunctive therapies, and potential novel agents for controlling Graves' hyperthyroidism.

EXPERT OPINION

Primary medical therapy is successful in less than 50% of cases and so careful selection of patients for medical treatment based on a combination of pathological and pragmatic considerations is essential. Carbimazole or methimazole is the treatment of choice in the non-pregnant population driven by its more favourable pharmacokinetic and adverse effect profile over propylthiouracil. In pregnancy the choice of treatment is less straightforward and an approach that minimises undue fetal exposure to all thionamides should be adopted. Additional data is needed on the value of adjunctive therapies including potassium perchlorate, iodides, glucocorticoids, lithium, and cholestyramine. Novel agents directed against pathogenetic targets including TSH receptor blocking monoclonal antibodies and small molecule antagonists may hold promise for the future.

Management of Neonates Born to Mothers With Graves' Disease

Neonates born to mothers with Graves' disease are at risk for significant morbidity and mortality and need to be appropriately identified and managed. Because no consensus guidelines regarding the treatment of these newborns exist, we sought to generate a literature-based management algorithm. The suggestions include the following: (1) Base initial risk assessment on maternal thyroid stimulating hormone (TSH) receptor antibodies. If levels are negative, no specific neonatal follow-up is necessary; if unavailable or positive, regard the newborn as "at risk" for the development of hyperthyroidism. (2) Determine levels of TSH-receptor antibodies in cord blood, or as soon as possible thereafter, so that newborns with negative antibodies can be discharged from follow-up. (3) Measurement of cord TSH and fT4 levels is not indicated. (4) Perform fT4 and TSH levels at day 3 to 5 of life, repeat at day 10 to 14 of life and follow clinically until 2 to 3 months of life. (5) Use the same testing schedule in neonates born to mothers with treated or untreated Graves' disease. (6) When warranted, use methimazole (MMI) as the treatment of choice; β-blockers can be added for sympathetic hyperactivity. In refractory cases, potassium iodide may be used in conjunction with MMI. The need for treatment of asymptomatic infants with biochemical hyperthyroidism is uncertain. (7) Assess the MMI-treated newborn on a weekly basis until stable, then every 1 to 2 weeks, with a decrease of MMI (and other medications) as tolerated. MMI treatment duration is most commonly 1 to 2 months. (8) Be cognizant that central or primary hypothyroidism can occur in these newborns.

Antithyroid Drug Use in Pregnancy and Birth Defects: Why Some Studies Find Clear Associations, and Some Studies Report None

BACKGROUND

Rare cases of birth defects after the use of methimazole (MMI) or carbimazole to treat hyperthyroidism in early pregnancy have been reported since 1972, whereas propylthiouracil (PTU) has not been considered teratogenic. Recently, two studies reported birth defects after the use of MMI in early pregnancy to affect 2-4% of exposed children, and one study also found birth defects after the use of PTU. On the other hand, some published studies did not find associations between the use of thionamides and birth defects.

SUMMARY

The methods used in the two positive and the four negative reports are reviewed. The two positive studies included a sufficient number of children exposed to MMI (n = 1231 and 1097) to evaluate the studied outcomes, whereas the four negative studies included a much lower number of exposed children (n = 73, 108, 30, and 124). Considering PTU, the birth defects observed in one study were in general milder and tended to be diagnosed and registered only when they resulted in complications and led to surgery after one year of age. None of the negative studies has investigated outcomes after one year of age.

CONCLUSION

Studies finding no associations between early pregnancy exposure to antithyroid drugs and birth defects were either not sufficiently powered or did not study outcomes at optimal ages.

Risk of congenital anomalies associated with antithyroid treatment during pregnancy: a meta-analysis

To evaluate the association of either propylthiouracil or methimazole treatment for hyperthyroidism during pregnancy with congenital malformations, relevant studies were identified by searching Medline, PubMed, the Cochrane Library and EMBASE. We intended to include randomized controlled trials, but no such trials were identified. Thus, we included cohort studies and case-control studies in this meta-analysis. A total of 7 studies were included in the meta-analyses. The results revealed an increased risk of birth defects among the group of pregnant women with hyperthyroidism treated with methimazole compared with the control group (odds ratio 1.76, 95% confidence interval 1.47-2.10) or the non-exposed group (odds ratio 1.71, 95% confidence interval 1.39-2.10). A maternal shift between methimazole and propylthiouracil was associated with an increased odds ratio of birth defects (odds ratio 1.88, 95% confidence interval 1.27-2.77). An equal risk of birth defects was observed between the group of pregnant women with hyperthyroidism treated with propylthiouracil and the non-exposed group (odds ratio 1.18, 95% confidence interval 0.97-1.42). There was only a slight trend towards an increased risk of congenital malformations in infants whose mothers were treated with propylthiouracil compared with in infants whose mothers were healthy controls (odds ratio 1.29, 95% confidence interval 1.07-1.55). The children of women receiving methimazole treatment showed an increased risk of adverse fetal outcomes relative to those of mothers receiving propylthiouracil treatment. We found that propylthiouracil was a safer choice for treating pregnant women with hyperthyroidism according to the risk of birth defects but that a shift between methimazole and propylthiouracil failed to provide protection against birth defects.

Congenital anomalies in children exposed to antithyroid drugs in-utero: a meta-analysis of cohort studies

Background

Hyperthyroidism affects about 0.2%-2.7% of all pregnancies, and is commonly managed with antithyroid drugs (ATDs). However, previous studies about the effects of ATDs on congenital anomalies are controversial. Therefore, the present meta-analysis was performed to explore the risk of congenital anomalies in children exposed to ATDs in-utero.

Methods

Embase, Pubmed, Web of Knowledge, and BIOSIS Citation Index were searched to find out studies about congenital anomalies in children exposed to ATDs in-utero reported up to May 2014. The references cited by the retrieved articles were also searched. The relative risks (RRs) and confidence intervals (CIs) for the individual studies were pooled by fixed effects models, and heterogeneity was analyzed by chi-square and I² tests.

Results

Eight studies met the inclusion criteria. Exposure to propylthiouracil (PTU), methimazole/carbimazole (MMI/CMZ), and PTU & MMI/CMZ was investigated in 7, 7 and 2 studies, respectively. The pooled RR was 1.20 (95%CI: 1.02-1.42), 1.64 (95%CI: 1.39-1.92), and 1.83 (95%CI: 1.30-2.56) for congenital anomalies after exposure to PTU, MMI/CMZ, and PTU & MMI/CMZ, respectively.

Conclusions

The meta-analysis suggests that exposure to ATDs in-utero increases the risk of congenital anomalies. The use of ATDs in pregnancy should be limited when possible. Further research is needed to delineate the exact teratogenic risk for particular congenital anomaly.

Craniosynostosis and risk factors related to thyroid dysfunction

Thyroid disease is a common problem among women of reproductive age but often goes undiagnosed. Maternal thyroid disease has been associated with increased risk of craniosynostosis. We hypothesized that known risk factors for thyroid disease would be associated with risk of craniosynostosis among women not diagnosed with thyroid disease. Analyses included mothers of 1,067 cases and 8,494 population-based controls who were interviewed for the National Birth Defects Prevention Study. We used multivariable logistic regression to estimate adjusted odds ratios (AOR) and 95% confidence intervals (CI). After excluding women with diagnosed thyroid disease, younger maternal age (AOR 0.7, 95% CI 0.6-0.9, for <25 years versus 25-29), black or other race-ethnicity (AOR 0.3, 95% CI 0.2-0.4 and AOR 0.6, 95% CI 0.4-0.8, respectively, relative to non-Hispanic whites), fertility medications or procedures (AOR 1.5, 95% CI 1.2-2.0), and alcohol consumption (AOR 0.8, 95% CI 0.7-0.9) were associated with risk of craniosynostosis, based on confidence intervals that excluded 1.0. These associations with craniosynostosis are consistent with the direction of their association with thyroid dysfunction (i.e., younger age, black race-ethnicity and alcohol consumption are associated with reduced risk and fertility problems are associated with increased risk of thyroid disease). This study thus provides support for the hypothesis that risk factors associated with thyroid dysfunction are also associated with risk of craniosynostosis. Improved understanding of the potential association between maternal thyroid function and craniosynostosis among offspring is important given that craniosynostosis carries significant morbidity and that thyroid disease is under-diagnosed and potentially modifiable.

Severity of birth defects after propylthiouracil exposure in early pregnancy

BACKGROUND

Propylthiouracil (PTU) used in the treatment of maternal hyperthyroidism in early pregnancy may be associated with a higher prevalence of birth defects in the face and neck region and in the urinary system but the severity of these complications remains to be elucidated.

METHODS

Review of hospital-registered cases of birth defects in the face and neck region and in the urinary system after PTU exposure in early pregnancy. We obtained information on maternal redeemed prescription of PTU and child diagnosis of birth defect from nationwide registers for all children born in Denmark between 1996 and 2008 (n=817,093). The children were followed until December 31, 2010 (median age, 8.3 years) and the Cox proportional hazards model was used to estimate adjusted hazard ratio (HR) with 95% confidence interval (CI) for having a birth defect after PTU exposure versus nonexposed children (n=811,730).

RESULTS

Fourteen cases of birth defects were identified in the face and neck region and in the urinary system after PTU exposure in early pregnancy; 11 children were exposed to PTU only (n=564), whereas 3 children were born to mothers who switched from methimazole (MMI)/carbimazole (CMZ) to PTU in early pregnancy (n=159). Among children exposed to PTU only, the adjusted HR for having a birth defect in the face and neck region was 4.92 (95% CI 2.04-11.86) and in the urinary system 2.73 (1.22-6.07). Looking into details of the 14 cases, 7 children were diagnosed with a birth defect in the face and neck region (preauricular and branchial sinus/fistula/cyst) and 7 children had a birth defect in the urinary system (single cyst of kidney and hydronephrosis). Surgical treatment was registered in 6 of the cases with a birth defect in the face and neck region and 3 of the cases with a birth defect in the urinary system. Two of the children with a birth defect in the urinary system also had other birth defects (genital organs).

CONCLUSIONS

We report details on possible PTU-associated birth defects. They tend to be less severe than the defects observed after MMI/CMZ exposure. Yet, the majority of affected children had to undergo surgery.

Therapy of endocrine disease: antithyroid drug use in early pregnancy and birth defects: time windows of relative safety and high risk?

BACKGROUND

Antithyroid drugs (ATDs) may have teratogenic effects when used in early pregnancy.

OBJECTIVE

To review the association between the time period of ATD exposure in early pregnancy and the development of birth defects.

METHODS

We identified publications on birth defects after early pregnancy exposure to the ATDs methimazole (MMI; and its prodrug carbimazole (CMZ)) and propylthiouracil (PTU). Cases of birth defects after ATD treatment had been initiated or terminated within the first 10 weeks of pregnancy were identified and studied in detail.

RESULTS

A total of 92 publications were read in detail. Two recent large controlled studies showed ATD-associated birth defects in 2-3% of exposed children, and MMI/CMZ-associated defects were often severe. Out of the total number of publications, 17 included cases of birth defects with early pregnancy stop/start of ATD treatment, and these cases suggested that the high risk was confined to gestational weeks 6-10, which is the major period of organogenesis. Thus, the cases reported suggest that the risk of birth defects could be minimized if pregnant women terminate ATD intake before gestational week 6.

CONCLUSION

Both MMI and PTU use in early pregnancy may lead to birth defects in 2-3% of the exposed children. MMI-associated defects are often severe. Proposals are given on how to minimize the risk of birth defects in fertile women treated for hyperthyroidism with ATDs.

Thyroid disease during pregnancy: options for management

Thyroid diseases affect up to 5% of all pregnancies. Adverse pregnancy and neonatal outcomes are increased by maternal thyroid disease and adequate treatment is thought to reduce these risks. Hypothyroidism is commonly treated with levothyroxine, with pregnancy increasing levothyroxine requirements in most women treated for hypothyroidism. Hyperthyroidism is often treated with antithyroid drugs in pregnancy. However, they are not completely safe to use during pregnancy as methimazole increases risk of neonatal malformations and propylthiouracil increases risk of maternal hepatotoxicity. Propylthiouracil is recommended to be used during the first trimester and switch to methimazole is recommended thereafter to reduce risk of hepatotoxicity. The treatment goal for hypothyroidism and hyperthyroidism is to achieve euthyroidism quickly and maintain it throughout pregnancy. Autoimmune thyroiditis and isolated maternal hypothyroxinemia do not currently warrant treatment during pregnancy, unless hypothyroidism ensues. Treatment of thyroid nodules and differentiated thyroid cancer can generally be safely postponed until after delivery.

Hyperthyroidism in pregnancy

Changes in thyroid hormone concentrations that are characteristic of hyperthyroidism must be distinguished from physiological changes in thyroid hormone economy that occur in pregnancy, especially in the first trimester. Approximately one to two cases of gestational hyperthyroidism occur per 1000 pregnancies. Identification of hyperthyroidism in a pregnant woman is important because adverse outcomes can occur in both the mother and the offspring. Graves' disease, which is autoimmune in nature, is the usual cause; but hyperthyroidism in pregnancy can be caused by any type of hyperthyroidism--eg, toxic multinodular goitre or solitary autonomously functioning nodule. Gestational transient thyrotoxicosis is typically reported in women with hyperemesis gravidarum, and is mediated by high circulating concentrations of human chorionic gonadotropin. Post-partum thyroiditis occurs in 5-10% of women, and many of those affected ultimately develop permanent hypothyroidism. Antithyroid drug treatment of hyperthyroidism in pregnant women is controversial because the usual drugs--methimazole or carbimazole--are occasionally teratogenic; and the alternative--propylthiouracil--can be hepatotoxic. Fetal hyperthyroidism can be life-threatening, and needs to be recognised as soon as possible so that treatment of the fetus with antithyroid drugs via the mother can be initiated. In this Review, we discuss physiological and pathophysiological changes in thyroid hormone economy in pregnancy, the diagnosis and management of hyperthyroidism during pregnancy, severe life-threatening thyrotoxicosis in pregnancy, neonatal thyrotoxicosis, and post-partum hyperthyroidism.

Esophageal atresia, small omphalocele and ileal prolapse through a patent omphalomesenteric duct: a methimazole embryopathy? [Corrected]

Newborns prenatally exposed to methimazole (active metabolite of carbamizole) for maternal hyperthyroidism may present some disorders in common, but the phenotype is not well defined. Choanal atresia is the most frequent, and other anomalies such as esophageal atresia and aplasia cutis were described with this embryopathy. Additionally, patent omphalomesenteric duct or Meckel's diverticulum in similar association was reported in some patients. The predisposed genetic background has to be considered. We report the case of a newborn exposed to carbamizole during the first 4 weeks of pregnancy and define an association related to prenatal methamizole exposure consisting of esophageal atresia, small omphalocele, and ileal prolapse through a patent omphalomesenteric duct.