Prevalence of overt and subclinical thyroid dysfunction among pregnant women and its effect on maternal and fetal outcome

Impact of maternal thyroid dysfunction on fetal and maternal outcomes in pregnancy: a prospective cohort study

BACKGROUND

Thyroid dysfunction in pregnancy can adversely impact maternal and fetal outcomes. However, the association between thyroid status and specific adverse outcomes needs clarity, especially in understudied regions.

OBJECTIVE

This prospective cohort study aimed to illuminate the multifaceted associations between maternal thyroid dysfunction and feto-maternal outcomes in Gujarat, India.

METHODS

This hospital-based cohort study recruited and monitored 500 euthyroid, 250 hypothyroid, and 150 hyperthyroid pregnant women until delivery. Maternal thyroid status was determined by serum thyroid stimulating hormone (TSH) and free thyroxine (fT4) levels. Adverse fetal outcomes included preterm birth, neonatal intensive care unit (NICU) admission, respiratory issues, and low APGAR scores. Maternal outcomes included preeclampsia, haemorrhage, hypertension, postpartum thyroiditis, and thromboembolism. Relative risks quantified associations between thyroid dysfunction and outcomes.

RESULTS

Compared to euthyroid women, hypothyroid women had a higher RR for preterm birth (RR 1.8, 95% CI 1.1-3.0), low APGAR score (RR 2.5, 95% CI 1.5-4.1), preeclampsia (RR 3.0, 95% CI 1.9-4.8), postpartum haemorrhage (RR 1.6, 95% CI 1.2-2.1), and venous thromboembolism (RR 3.1, 95% CI 1.7-5.7). Hyperthyroid women had over twice the risk of low APGAR score (RR 1.8, 95% CI 0.9-3.5), neonatal hypoglycemia (RR 1.5, 95% CI 0.5-4.3), respiratory distress (RR 1.4, 95% CI 0.7-2.8), and postpartum thyroiditis (RR 2.3, 95% CI 1.1-4.8).

CONCLUSION

Maternal thyroid dysfunction escalates risks for adverse fetal and maternal outcomes. Thyroid monitoring and management during pregnancy are critical to mitigate complications.

Prevalence of thyroid disorder in pregnant ladies among Maharashtrian women

Thyroid disorders during pregnancy lead to maternal outcome and foetal outcome. Therefore, it is of interest to evaluate the prevalence of thyroid disorders in pregnancy and its correlation with maternal outcome and foetal outcome. Hence, 450 pregnant female patients were investigated on the basis of detailed history, clinical information and lab investigation to record maternal outcome and foetal outcome for Hyperthyroidism and hypothyroidism disorders. Data shows that those who had received treatment for hypothyroidism has less complications compared to those who had not received treatment. Thus, hypothyroidism warrants careful management to mitigate associated risks and complications.

Prevalence and Pattern of Gestational Thyroid Dysfunction in a Population of South-East Nigerian Women

Background

Pregnancy serves as a physiological stress test for the thyroid which often leads to dysfunction in women with limited thyroid reserves. The occurrence of gestational thyroid dysfunction is linked to unfavourable obstetric and foetal outcomes. Globally, iodine deficiency is a prominent causative factor for thyroid dysfunction. The study aimed to determine the prevalence and pattern of thyroid dysfunction among pregnant women in Enugu, South-east Nigeria.

Methodology

This hospital-based descriptive cross-sectional and observational study was conducted over six months on selected participants from pregnant women attending antenatal clinics at the study sites. Maternal clinical and demographic risk factors for thyroid dysfunction were evaluated in a cohort of 318 pregnant women. An analysis of variance (ANOVA) was performed to compare participants' thyroid status across different trimesters of pregnancy, and different thyroid and nutritional iodine states.

Results

The prevalence of thyroid dysfunction in the study population is 6.6%. Hypothyroidism was detected in 5.3% of the participants, consisting of 3.8% sub-clinical hypothyroidism and 1.6% overt hypothyroidism. Sub-clinical hyperthyroidism accounted for 1.3% of all participants; no overt hyperthyroidism was detected in this study.

Conclusion

There is a relatively high prevalence of gestational thyroid dysfunction in the study population with hypothyroidism being the predominant disorder. This highlights the need for region-specific considerations in antenatal care to facilitate early detection and effective management of gestational thyroid dysfunction, thereby mitigating potential adverse maternal and foetal outcomes.

Early treatment will prevent feto-maternal complications in thyroid disorders during pregnancy: A prospective study

Context

Associations between adverse maternal complications and fetal outcomes are known entity in thyroid disorders during pregnancy. Thus, prompt identification of thyroid disorders and timely initiation of treatment is essential. Universal screening and early treatment of pregnant women for thyroid disorder should be considered especially in a resource-limited country like India with a high prevalence of undiagnosed thyroid disorders and adverse feto-maternal outcomes.

Aims

Early treatment will prevent feto-maternal complications in thyroid disorders in pregnant females visiting outpatient department in tertiary care hospital in rural settings.

Settings and Design

This study was conducted in a tertiary care rural-based medical college with participation from departments of Obstetrics and Gynaecology, Medicine, and ENT.

Methods and Material

Expectant mothers in first trimester who had urine pregnancy test positive in outpatient clinic were included after a written informed consent. Detailed history and examination was done. TSH was done if abnormal-FT3 and FT4 were done. All thyroid disorders were treated according to American Thyroid Association (ATA) 2017 guideline. All pregnancies were followed up for maternal complications and fetal outcomes.

Statistical Analysis Used

Data from the performa were entered in Office Excel and analysis was performed using STATA (14.2). Descriptive statistics (mean [standard deviation], Frequency [%], etc.) were used to depict profile of study participants, prevalence of thyroid dysfunction, and outcome measures. Chi-square test was employed to assess the association between thyroid dysfunction and various maternal and fetal outcomes. A P value less than. 05 was considered statistically significant.

Results

Of 350 pregnant females, 83 (23.5%) pregnant females had thyroid disorder. Of which, 33 (9.4%) had subclinical hypothyroidism, 37 (10.5%) had overt hypothyroidism, 11 (3.1%) had subclinical hyperthyroidism, and two (0.5%) had hyperthyroidism. The prevalence of hypothyroidism in pregnancy increases with increasing age (P value. 001) and not associated with parity, abortion, and consumption of iodized salt. Total patients with feto-maternal outcome follow-up were 241. Pre-eclampsia (P value. 004) was a significant complication in hypothyroid mothers. There was no significant difference in the rate of cesarean section and preterm delivery in hypothyroid and euthyroid mothers. Neonatal outcomes showed more trends of abortion, fetal demise, and IUFD in the hypothyroid group, although not statistically significant. (P value. 07).

Conclusions

Due to the high prevalence of thyroid disorders during pregnancy, universal screening of thyroid disorders should be done in early pregnancy instead of high-risk screening. Early detection and early treatment in the first 10 weeks of pregnancy help to prevent maternal and fetal complications of thyroid disorders in pregnancy. Pre-eclampsia is to be monitored in treated pregnant females with hypothyroidism.

Prevalence, risk factors, and consequences of hypothyroidism among pregnant women in the health region of Lleida: A cohort study

BACKGROUND

Primary maternal hypothyroidism is defined as the increase of TSH levels in serum during pregnancy. Hypothyroidism in pregnancy is the second most common endocrine disease, after diabetes mellitus, with a prevalence ranging between 3.2 and 5.5%. Its variability depends on ethnical differences. Hypothyroidism in pregnancy is associated with other chronic diseases and fetal and maternal outcomes.

OBJECTIVE

To analyze the prevalence of hypothyroidism among multiethnic pregnant women, and to evaluate the comorbidity with chronic diseases and outcomes leaded during pregnancy and newborn.

METHODS

Retrospective observational cohort study in pregnant women during the years 2012-2018 in the health region of Lleida. The relationship of hypothyroidism with different variables was analyzed by calculating the adjusted odds ratio (aOR) and the 95% confidence intervals (CI) with multivariate logistic regression models.

RESULTS

We analyzed a sample of 17177 pregnant women, which represents more than 92% of the total of pregnant women in the health region of Lleida. The annual prevalence of hypothyroidism was 5.7-7.1%. According to the region of origin, the lowest prevalence was found in the population from Sub Saharian Africa (2.1%), while the highest was from Asia and the Middle East (8.6%). Other factors associated with hypothyroidism were age, hypertension, diabetes mellitus, and dyslipidemia. In addition, we did not observe an effect of hypothyroidism on the course of pregnancy, childbirth, and on the newborn. Finally, there was a good control of the disease during pregnancy.

CONCLUSIONS

The prevalence of hypothyroidism in pregnancy was 6,5% in this study which depends on the country of origin, lower values were found in Sub Saharian African women and higher in those from Asia and the Middle East. Hypothyroidism was associated with age, diabetes mellitus, arterial hypertension, or dyslipidemia, and was not related to the Apgar score or the weight of the newborn.

Maternal hypothyroidism in rats impairs placental nutrient transporter expression, increases labyrinth zone size, and impairs fetal growth

INTRODUCTION

Hypothyroidism during pregnancy is associated with fetal growth restriction (FGR). FGR is commonly caused by placental insufficiency and yet the role of hypothyroidism in placental regulation of fetal growth is unknown. This study aimed to investigate the effects of maternal hypothyroidism on placental nutrient transporter expression, placental morphology, and placental metabolism.

METHODS

Hypothyroidism was induced in female Sprague-Dawley rats by adding methimazole (MMI) to drinking water at moderate (MOD, MMI at 0.005% w/v) and severe (SEV, MMI at 0.02% w/v) doses from one week prior to pregnancy and throughout gestation. Maternal and fetal tissues were collected on embryonic day 20 (E20).

RESULTS

Hypothyroidism reduced fetal weight (PTrt<0.001) despite causing fetal hyperglycaemia (PTrt = 0.016). Placental weight was not affected by hypothyroidism however placental efficiency was reduced (PTrt<0.001), as was the junctional zone (JZ):labyrinth zone (LZ) weight ratio (PTrt = 0.005). LZ glycogen content was increased (PTrt = 0.029) and while mRNA expression of glucose transporters was reduced by hypothyroidism, only GLUT1 protein expression was reduced in male LZs. Maternal hypothyroidism reduced mitochondrial content (PTrt = 0.031), particularly in SEV males relative to CON males (P = 0.004). Protein expression of Complex V (P < 0.001) and Complex III (P = 0.002) of the electron transport chain were also reduced in males. Maternal hypothyroidism reduced LZ (PTrt<0.001) and fetal plasma triglycerides (P = 0.019) while fetal free fatty acids and the expression of LZ lipid transporters was not affected.

DISCUSSION

Overall, maternal hypothyroidism may lead to FGR through reduced maternal T4 availability, changes to placental morphology, altered nutrient transporter expression and sex-specific effects on placental metabolism. Changes to LZ glycogen and triglyceride stores as well as mitochondrial content suggest a metabolic shift from oxidative phosphorylation to anaerobic glycolysis in males. These changes also likely impact fetal substrate availability and therefore fetal growth.

Neonatal Screening for Congenital Hypothyroidism in Preterm Infants: Is a Targeted Strategy Required?

Background: Premature infants are at higher risk of developing congenital hypothyroidism (CH) but the neonatal screening strategy for this population is still debatable. The purpose of this retrospective study is to describe the results of a screening program for CH in a preterm infant cohort. Materials and Methods: All preterm newborns who underwent neonatal screening in the Italian region of Piedmont in the period January 2019-December 2021, were included in this retrospective cohort study. The first thyrotropin (TSH) measurement was performed at 72 hours, whereas the second at 15 days of life. Infants with TSH >20 mUI/L at first detection and >6 mUI/L at second were recalled for a full evaluation of thyroid function. Results: During the study period, 5930 preterm newborns were screened. Based on birthweight (BW), the mean TSH was 2.08 ± 0.15 for BW <1000 g, 2.01 ± 0.02 for BW 1001-1500 g, 2.28 ± 0.03 for BW 1501-2499 g, and 2.41 ± 0.03 mUI/L in normal-weight newborns (p < 0.005) at the first detection, with a significant difference observed at the second measurement (p < 0.005). Based on gestational age, the mean TSH at first detection was 1.71 ± 0.09 mUI/L for extremely preterm babies and 1.87 ± 0.06, 1.94 ± 0.05, and 2.42 ± 0.02 mUI/L for very preterm, moderately, and late preterm infants (p < 0.005), respectively. Significant between-group differences of TSH measurements were also at the second and third detections (p < 0.005 and p = 0.01). The 99% reference range in this cohort overlapped with the recommended TSH cutoffs for screening recall (8 mUI/L for first detection and 6 mUI/L for second detection). CH incidence was 1:156. Of the 38 patients diagnosed with CH, a eutopic gland was present in 30 (87.9%), with CH transient in 29 (76.8%). Conclusions: We observed no significant difference in the recall rate between preterm and at term infants screened in this study. Our current screening strategy therefore appears effective in avoiding misdiagnosis. CH screening approaches vary among countries. Development and testing of a uniform multinational screening strategy is needed.

Maternal subclinical hyperthyroidism and adverse pregnancy outcomes considering the iodine status: Tehran thyroid and pregnancy study

BACKGROUND

Unlike overt thyroid diseases, the impacts of subclinical thyroid dysfunction, especially subclinical hyperthyroidism (SH), on adverse pregnancy outcomes are inconclusive.

OBJECTIVE

We aimed to investigate the effect of maternal SH on adverse maternal and neonatal outcomes based on urinary iodine concentration (UIC).

METHODS

A secondary analysis was run on data collected in the Tehran Thyroid and Pregnancy study (TTPs). We used the data of 131 women with SH and 1650 cases of euthyroid. Serum levels of thyroid-stimulating hormone (TSH), thyroxine (T4), free thyroxine index (FT4I), and thyroid peroxidase antibody (TPOAb) were assessed at the first prenatal visit. A generalized linear regression model was applied to identify the effect of SH on the pregnancy outcomes based on UIC, and the effects were estimated with a 95% confidence interval.

RESULTS

Preterm delivery was observed in 12.3% of women with SH and 6.7% of those with euthyroid (P = 0.03). Women with TSH< 0.3 mIU/L had a higher odds of preterm delivery than those with TSH≥ 0.3 regardless of urine iodine cut-off [OR= 2.27; 95% CI: (1.15, 4.48), p = 0.02]. Among those with UIC levels≥ 150 μg/L, the odds ratio of preterm delivery was 4.61 folds higher in the SH group compared to those with euthyroid [95%CI: (1.36, 15.71), p = 0.01)]. No significant difference between these two study groups was found in Neonatal Intensive Care Unit admission. Moreover, the results revealed no statistically significant difference in the means of neonatal anthropometric parameters in the SH and euthyroid groups in none of the subgroups of UIC (<150 or ≥150 µg/l).

CONCLUSIONS

According to our results, maternal SH appears to be a risk factor for preterm delivery. This effect is more pronounced in women with higher UIC than those with lower UIC.

Maternal Subclinical Hyperthyroidism and Adverse Pregnancy Outcomes: A Systematic Review and Meta-analysis of Observational Studies

CONTEXT

Findings from studies evaluating adverse pregnancy outcomes in pregnant women with subclinical hyperthyroidism are conflicting and inconclusive.

OBJECTIVES

In this systematic review and meta-analysis, our aim was to evaluate the pooled odds ratio (OR) of adverse pregnancy outcomes in women with subclinical hyperthyroidism, compared to euthyroid women.

DATA SOURCES

Scopus, PubMed (including Medline), and Web of Science databases were systemically searched for regaining published studies to January 2022 examining adverse pregnancy outcomes in women with subclinical hyperthyroidism.

STUDY SELECTION

Outcomes of interest were classified into seven composite outcomes, including hypertensive disorders, preterm delivery, macrosomia/large for gestational age (LGA), pregnancy loss, adverse maternal outcomes, adverse neonatal outcomes, and adverse fetal outcomes.

DATA EXTRACTION

In this meta-analysis, both fixed and random effect models were used. Publication bias was also evaluated by Egger test and the funnel plot, and the trim and fill method was conducted in case of a significant result, to adjust the bias.

RESULTS

Of 202 records retrieved through searching databases, 11 studies were selected for the final analyses. There were no significant differences in pooled ORs of hypertensive disorders, preterm delivery, macrosomia/LGA, and pregnancy loss in pregnant women with subclinical hyperthyroidism, compared to the euthyroid controls. The pooled OR of adverse maternal, neonatal, and fetal outcomes in pregnant women with subclinical hyperthyroidism was not statistically significantly different from that of the euthyroid control group.

CONCLUSIONS

The current meta-analysis demonstrated that subclinical hyperthyroidism in pregnancy is not related with adverse maternal and fetal outcomes. Therefore, clinicians should be avoided unnecessary treatments for pregnant women with subclinical hyperthyroidism.

Subclinical hypothyroidism in women's health: from pre- to post-menopause

OBJECTIVE

Subclinical hypothyroidism (SCH) is a quite frequent condition among women, affecting 3-12% of the general population. Its consequences on women's health in reproductive age, pregnancy and menopause have been extensively investigated but data about the effective impact of treatment with levothyroxine (LT4) remain conflicting.

METHODS

This is a narrative review and analysis of the most relevant data until June 2021.

RESULTS

SCH may affect reproduction. Evidence suggests that women with SCH undergoing assisted reproductive technique (ART) may benefit from LT4 therapy whereas there are no conclusive data regarding women attempting natural conception. SCH may be associated with several negative pregnancy outcomes, that is to say recurrent pregnancy loss (RPL), preterm delivery, preeclampsia and neurocognitive disturbances of offspring. However, the protective role of LT4 treatment has been established in selected cases, for instance in thyroid peroxidase antibody (TPOAb) -positive women with TSH greater than the pregnancy specific reference range and/or in TPOAb-negative women with TSH >10.0 mIU/L. In menopause, SCH can worsen the negative cardio-metabolic effects of hormonal loss and/or aging, by exacerbating dyslipidaemia and hypertension. Nevertheless, robust data about the benefits of LT4 therapy are still lacking and treatment should be encouraged with caution.

CONCLUSIONS

SCH represents a challenging condition during pre- and post- menopause. An aware knowledge of its possible principal consequences could help all clinicians who are involved in women's health to manage more properly it, preventing its sequelae.

Effect of Hyperthyroidism Control During Pregnancy on Maternal and Fetal Outcome: A Systematic Review and Meta-Analysis

CONTEXT

Although the overt hyperthyroidism treatment during pregnancy is mandatory, unfortunately, few studies have evaluated the impact of treatment on reducing maternal and fetal outcomes.

OBJECTIVE

This study aimed to demonstrate whether treatment to control hyperthyroidism manifested during pregnancy can potentially reduce maternal-fetal effects compared with euthyroid pregnancies through a systematic review with meta-analysis.

DATA SOURCE

MEDLINE (PubMed), Embase, Cochrane Library Central, LILACS/BIREME until May 2021.

STUDY SELECTION

Studies that compared, during the gestational period, treated women with hyperthyroidism versus euthyroid women. The following outcomes of this comparison were: pre-eclampsia, abruptio placentae, fetal growth retardation, gestational diabetes, postpartum hemorrhage, low birth weight, stillbirth, spontaneous abortions, premature birth.

DATA EXTRACTION

Two independent reviewers extracted data and performed quality assessments. Dichotomous data were analyzed by calculating risk differences (DR) with fixed and random effect models according to the level of heterogeneity.

DATA SYNTHESIS

Seven cohort studies were included. The results of the meta-analysis indicated that there was a lower incidence of preeclampsia (p=0.01), low birth weight (p=0.03), spontaneous abortion (p<0.00001) and preterm birth (p=0.001) favouring the euthyroid pregnant group when compared to those who treated hyperthyroidism during pregnancy. However, no statistically significant differences were observed in the outcomes: abruptio placentae, fetal growth retardation, gestational diabetes mellitus, postpartum hemorrhage, and stillbirth.

CONCLUSIONS

Our findings demonstrated that treating overt hyperthyroidism in pregnancy is mandatory and appears to reduce some potential maternal-fetal complications, despite there still being a residual risk of negative outcomes.

Prevalence of Subclinical Hypothyroidism in Pregnancy and Its Association With Anti-thyroperoxidase Antibody and the Occurrence of Gestational Diabetes Mellitus

Introduction Subclinical hypothyroidism (SCH) and gestational diabetes mellitus (GDM) are common endocrinological abnormalities associated with pregnancy. The presence of a raised anti-thyroperoxidase (anti-TPO) antibody titer increases the risk of progression of subclinical hypothyroidism to overt hypothyroidism. Subclinical hypothyroidism and GDM are known to affect maternal and fetal outcomes adversely. A few studies have shown an increased risk of GDM with autoimmune hypothyroidism. However, data regarding this association between GDM, SCH, and anti-TPO Ab are scarce. This study aimed to find the prevalence of autoimmune subclinical hypothyroidism and its association with GDM in pregnancy. Materials and methods In a cross-sectional study, 382 pregnant women at their first antenatal checkup (ANC) were enrolled in the study. Serum thyroid-stimulating hormone (TSH), free T4 (FT4), anti-TPO Ab, and the 75 g oral glucose tolerance test (OGTT) were evaluated. The results obtained were analyzed in Systat Version 13.2 (SPSS Inc., Chicago, IL). Observations Results showed an SCH prevalence of 37.69% with a raised anti-TPO Ab titer in 49.31% of the diagnosed SCH cases, pointing towards an autoimmune etiology. Our study revealed a GDM prevalence of 12.04%. Out of the 46 GDM cases, 16 were found to have SCH and 3 cases had raised anti-TPO Ab titers. In our study, 27.73% of euthyroid pregnant women had a raised anti-TPO Ab titer. Our study revealed no significant association between GDM, SCH, and raised anti-TPO Ab titer. Conclusion Anti-TPO antibody subsequently leads to hypothyroxinemia, for which it is necessary that cases with high titer of anti-TPO antibody though euthyroid should be meticulously followed up and screened for to detect development of hypothyroidism or SCH, particularly in future pregnancies. However, GDM prevalence was at par with the national figure, but with no significant association of SCH and a high anti-TPO ab titer was found with GDM in our study. Further studies with a larger cohort may establish a causal association between the two most common endocrinological disorders observed in pregnancy.

Congenital Hypothyroidism in Preterm Newborns - The Challenges of Diagnostics and Treatment: A Review

Preterm newborns are forced to adapt to harsh extrauterine conditions and endure numerous adversities despite their incomplete growth and maturity. The inadequate thyroid hormones secretion as well as the impaired regulation of hypothalamus-pituitary-thyroid axis may lead to hypothyroxinemia. Two first weeks after birth are pivotal for brain neurons development, synaptogenesis and gliogenesis. The decreased level of thyroxine regardless of cause may lead to delayed mental development. Congenital hypothyroidism (CH) is a disorder highly prevalent in premature neonates and it originates from maternal factors, perinatal and labor complications, genetic abnormalities, thyroid malformations as well as side effects of medications and therapeutic actions. Because of that, the prevention is not fully attainable. CH manifests clinically in a few distinctive forms: primary, permanent or transient, and secondary. Their etiologies and implications bear little resemblance. Therefore, the exact diagnosis and differentiation between the subtypes of CH are crucial in order to plan an effective treatment. Hypothyroxinemia of prematurity indicates dynamic changes in thyroid hormone levels dependent on neonatal postmenstrual age, which directly affects patient's maintenance and wellbeing. The basis of a successful treatment relies on an early and accurate diagnosis. Neonatal screening is a recommended method of detecting CH in preterm newborns. The preferred approach involves testing serum TSH and fT4 concentrations and assessing their levels according to the cut-off values. The possible benefits also include the evaluation of CH subtype. Nevertheless, the reference range of thyroid hormones varies all around the world and impedes the introduction of universal testing recommendations. Unification of the methodology in neonatal screening would be advantageous for prevention and management of CH. Current guidelines recommend levothyroxine treatment of CH in preterm infants only when the diagnose is confirmed. Moreover, they underline the importance of the re-evaluation among preterm born infants due to the frequency of transient forms of hypothyroidism. However, results from multiple clinical trials are mixed and depend on the newborn's gestational age at birth. Some benefits of treatment are seen especially in the preterm infants born <29 weeks' gestation. The discrepancies among trials and guidelines create an urgent need to conduct more large sample size studies that could provide further analyses and consensus. This review summarizes the current state of knowledge on congenital hypothyroidism in preterm infants. We discuss screening and treatment options and demonstrate present challenges and controversies.

Relationship Between Subclinical Hypothyroidism in Pregnancy and Hypertensive Disorder of Pregnancy: A Systematic Review and Meta-Analysis

OBJECTIVE

Studies have shown a high incidence of subclinical hypothyroidism in pregnancy, but the adverse pregnancy outcomes caused by it are not clear. Therefore, we conducted a systematic review and meta-analysis to evaluate the relationship between subclinical hypothyroidism in pregnancy and hypertensive disorders of pregnancy(HDP) to guide clinical practice.

METHOD

We searched the MEDLINE (PubMed), Cochrane Central, EMBASE, Web of Science, and SCOPUS databases and screened all studies evaluating the relationship between subclinical hypothyroidism in pregnancy and hypertensive disorders of pregnancy. Two researchers independently evaluated the quality of all eligible original studies using the Newcastle-Ottawa Scale (NOS). We also performed a meta-analysis using STATA15.1. Sensitivity analyses were also performed by examining the effects of individual studies as well as using different effect models and detecting any publication bias using the harbord test.

RESULTS

Twenty-two studies were included in the final meta-analysis. Our results indicated that pregnant women with subclinical hypothyroidism had an increased risk of HDP (OR = 1.54(95% CI: 1.21-1.96) I²=67.1%), compared with euthyroidism. Subclinical hypothyroidism in pregnancy was not associated with hypertensive disorders of pregnancy at TSH diagnostic cut-off of less than 3.0 mIU/L (P = 0.077). Curiously, the risk of HDP increases when the TSH diagnostic cut-off value is higher or lower than 4 mIU/L. Although only 9 studies were above the threshold, the risk of developing HDP was still 1.69 times, which was highest in all subgroup analyses. This is consistent with the newly recommended diagnostic cut-off value of 4 mIU/L for TSH by the ATA. Our results consider that the risk of hypertensive disorder complicating pregnancy is increased regardless of the diagnosis of subclinical hypothyroidism at any stage of pregnancy. Unfortunately, there is insufficient evidence to support that patients can benefit from treatment with levothyroxine.

CONCLUSION

The results of this meta-analysis indicate that subclinical hypothyroidism in pregnancy is associated with an increased risk of developing HDP, and this association exists regardless of the gestational period. However, the available evidence cannot support these patients receiving thyroxine intervention can benefit from it, so routine screening is only recommended for pregnant women with risk factors for hypothyroidism. Further research is needed to validate more scientific and rigorous clinical studies to clarify the relationship between subclinical hypothyroidism and HDP to improve patient prognosis.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, PROSPERO (CRD42021286405).

Reference Levels for TSH in Iodine-Sufficient Low-Risk Pregnant Women

Background

Recent evidence suggests that thyrotropin (TSH) levels are population specific because of differences in ethnicity. As a result, the 2017 ATA guidelines state that treatment may be tailored as per the laboratory-specific reference ranges of TSH for the local population instead of using a fixed upper limit of 2.5 mIU/L during pregnancy.

Methodology

This was a cross-sectional study in which we collected detailed clinical data of 604 pregnant women along with their TSH and spot urinary iodine excretion levels. Reflex testing for thyroid peroxidase antibodies (TPOAb) was done in women with TSH levels > 2.5 mIU/L in 1st trimester and 3.0 mIU/L in 2nd and 3rd trimester. After excluding 295 women who had high risk factors as per ATA 2017 guidelines and those who were TPOAb positive, we calculated the reference range for TSH in an iodine-sufficient low-risk cohort of 309 women.

Results

With median urinary Iodine of 255 µg/l, our population had more than required iodine levels. The 5th and 95th percentiles of TSH in our study cohort of 604 women were 0.64 and 7.81 mIU/L, respectively, while the 5th and 95th percentiles of TSH for the low-risk cohort of 309 women were 0.59 and 4.48 mIU/L, respectively.

Conclusion

An upper limit of 4.5 mIU/L for TSH level during pregnancy can be used to guide management decisions for low-risk North Indian women.

The Study of Prevalence and Pattern of Thyroid Disorder in Pregnant Women: A Prospective Study

Background The most frequent thyroid disorder in pregnancy is maternal hypothyroidism. The geographical variation in the prevalence of hypothyroidism during pregnancy is very wide and ranges from 2.5% to 11%. The prevalence of hypothyroidism is more in Asian countries as compared to western countries. Thus, this study was conducted to find out the prevalence of thyroid disorder in pregnancy at our center. Methods The present study was conducted in the Department of Physiology in collaboration with the Department of Obstetrics & Gynecology, Index Medical College, Hospital and Research Center, Indore, MP, India over a period of one and a half years from October 2018 to March 2020. It was a cross-sectional study including 865 pregnant women. The patients' demographic profile was noted in all cases. A detailed history and thorough examination were done in all cases. Serum thyroid-stimulating hormone (TSH), Free T3, and Free T4 (FT3 and FT4) were done along with routine blood investigations as per The Federation of Obstetric and Gynaecological Societies of India-Indian College of Obstetricians and Gynaecologists (FOGSI-ICOG) good clinical practice recommendation. Results In this study, the prevalence of thyroid dysfunction was 10.4%. Of these 90 patients with thyroid dysfunction, subclinical and overt hypothyroidism was found in 5.50% and 0.92%, respectively, whereas subclinical and overt hyperthyroidism was observed in 3.12% and 0.81% pregnant females, respectively. A significant association was found between thyroid dysfunction and maternal age, BMI, parity, and education. Conclusions The prevalence of thyroid dysfunction was 10.4% in this study. Hypothyroidism was more common than hyperthyroidism and subclinical thyroid disorders were more common than overt thyroid disorders in pregnancy. Therefore, we should include thyroid function tests with other routine investigations during pregnancy to detect thyroid dysfunction.

"Small Thyroid Gland" in Reproductive Women without Autoimmune Thyroid Disease-Ultrasonographic Evaluation as a Useful Screening Tool for Hypothyroidism

Proper thyroid function is important for women of childbearing age, as hypothyroidism affects fertility, pregnancy and offspring. The upper reference limit for thyrotropin (TSH) in pregnancy was defined as <2.5 mU/L in the first trimester. Recommendations include either universal screening of TSH before pregnancy, or identifying individuals at “high risk” for thyroid illness. “Small thyroid gland” not associated with autoimmune thyroid disease (AITD) seems to be a reason for hypothyroidism and probably should be included in target case finding procedure before pregnancy. The purpose of this cross-sectional study was to analyze relationships between the thyroid volume and its function, and to determine the thyroid volume as a predictive factor for TSH levels above 2.5 µIU/mL in reproductive women without AITD. We included 151 women without AITD, and aged 18–40. Blood and urine samples were analyzed for parameters of thyroid function. Ultrasound examination of the thyroid was performed. The thyroid volume was negatively correlated with TSH. Women with a thyroid volume in the 1st quartile for the study population presented higher TSH levels versus women in the 4th quartile (p = 0.0132). A thyroid volume cut-off point of 9 mL was the predictive factor for TSH levels above 2.5 µIU/mL (p = 0.0037).

Relationship between Thyroid Status during the First Trimester of Pregnancy and Neonatal Well-Being

Iodine is an essential micronutrient for the synthesis of thyroid hormones. The proper functioning of the thyroid axis is essential for the normal development of the nervous system, especially in the first trimester of gestation. The aim of the present study was to analyze the perinatal outcomes, anthropometry, and APGAR test scores of newborns and to relate them to maternal thyroid status. A total of 190 newborns participated in the study. No correlation was found between thyroid stimulating hormone (TSH) and maternal ioduria values in the first trimester of gestation with the weight or length of the newborn, or the APGAR score at one minute after birth. However, we found significant differences between the APGAR scores of children whose mothers had an iodine sufficiency level in the first trimester compared to the children of mothers with iodine deficiency. Similarly, the APGAR scores of children whose mothers had a TSH > 4 have significantly better APGAR scores than the children of mothers with a TSH < 4. Likewise, we found significant differences between the measurements of the newborns depending on whether their mothers smoked. The children of mothers who took iodine supplements or iodized salt obtained the highest APGAR score at one and five minutes after birth. It is essential to focus on recommending adequate consumption of iodine supplements and iodized salt prior to gestation and at least during the first trimester to achieve better fetal well-being.

Prevalence of Hypothyroidism in Pregnant Women in India: A Meta-Analysis of Observational Studies

INTRODUCTION

This meta-analysis was conducted to estimate the prevalence of hypothyroidism among pregnant women in India.

METHODS

We searched PubMed, Web of Science, Scopus, Google Scholar, and Shodhganga (Indian thesis repository) for observational studies, providing prevalence of hypothyroidism among pregnant women in India. Systematic study selection and data extraction procedures were followed. Quality assessment of each study was done using JBI critical appraisal checklist. The random effects model was used for pooling the effect sizes. Publication bias was assessed using the funnel plot and rank correlation test. I 2 statistics was used to measure heterogeneity across the studies. Heterogeneity in the pooled estimates was further explored with subgroup analyses and meta-regression analysis.

RESULTS

Sixty-one studies were found eligible and included in this review. The pooled estimate of the prevalence of hypothyroidism in pregnant women was 11.07% (95% CI: 8.79-13.84, I 2 = 99%). Pooled prevalence estimates of subclinical and overt hypothyroidism are 9.51% (95% CI: 7.48-12.04, I 2 = 98%) and 2.74% (95% CI: 2.08-3.58, I 2 = 94%).

CONCLUSION

We documented 11.07% pooled prevalence of hypothyroidism in pregnant women in India.

KK, Horo M, Shumayla S, Mehra S. Generating evidence on screening, diagnosis and management of non-communicable diseases during pregnancy; a scoping review of current gap and practice in India with a comparison of Asian context

BACKGROUND

Children born to high-risk pregnancies are more likely to experience adverse health outcomes later in life. As estimated, 15% of all pregnancies are at risk of various life-threatening conditions leading to adverse maternal and foetal outcomes. Millennium Development Goal resulted in the global reduction of maternal death from 390,000 to 275000 in 1990-2015). Similarly, to keep this momentum, the current United Nations Sustainable Development Goal (SDG: 3.1) aims at reducing the global maternal mortality ratio to less than 70 per 100,000 live births by 2030, and this can be achieved by addressing high-risk pregnancy contributing to significant mortality and morbidity. In India, gestational diabetes, gestational hypertension, and gestational hypothyroidism were identified as factors contributing to the high-risk pregnancy. This review summarises the commonly used approach for screening, diagnosis, and management of these conditions in the Asian population. It draws a comparison with the current protocols and guidelines in the Indian setting.

METHODS

Electronic search in PubMed and Google Scholar, reference snowballing, and review of current guidelines and protocols were done between January 2010 to October 2019. Published studies reporting Screening, diagnosis, and management of these conditions were included. Articles selected were then screened, appraised for quality, extract relevant data, and synthesised.

RESULTS

Screening, diagnosis, and management of these three conditions vary and no single universally accepted criteria for diagnosis and management exist to date. In India, national guidelines available have not been evaluated for feasibility of implementation at the community level. There are no national guidelines for PIH diagnosis and management despite the increasing burden and contribution to maternal and perinatal morbidity and mortality. Criteria for diagnosis and management of gestational diabetes, gestational hypertension, and gestational hypothyroidism varies but overall early screening for predicting risk, as reported from majority of the articles, were effective in minimizing maternal and foetal outcome.

CONCLUSION

Existing National guidelines for Screening, Diagnosis, and Management of Gestational Diabetes Mellitus (2018) and Gestational Hypothyroidism (2014) need to be contextualized and modified based on the need of the local population for effective treatment. Findings from this review show that early screening for predicting risk to be an effective preventive strategy. However, reports related to a definitive diagnosis and medical management were heterogeneous.

Prevalence of Thyroid Disorder in Pregnant Women Visiting a Tertiary Care Teaching Hospital: A Descriptive Cross-sectional Study

Introduction:

The function of the thyroid gland is altered during pregnancy. Thyroid disorders during pregnancy are associated with serious maternal and fetal outcomes. Universal screening for thyroid disorders is recommended in the first trimester of pregnancy. This study aims to determine the prevalence of thyroid disorder during pregnancy in women attending a tertiary care hospital.

Methods:

A descriptive cross-sectional study was conducted in the Department of Obstetrics and Gynaecology of Kathmandu Medical College and Teaching Hospital from March 2020 to August 2020 after obtaining ethical approval from the Institutional Review committee with reference number 20032020. The pregnant women >18 years of age, irrespective of their gestational age and gravida status, were included in the study by convenience sampling method. The participants were screened by estimation of thyroid function test. Data were collected, and statistical analysis was done in Statistical Packages for Social Services version 20.0.

Results:

A total of 329 pregnant women were included in this study. The prevalence of thyroid disorders in the present study is 24.62%. The most common thyroid disorder observed was subclinical hypothyroidism comprising 65 (19.75%) cases followed by overt hypothyroidism 8 (2.43%) cases.

Conclusions:

There is a high prevalence of thyroid disorders during pregnancy in our settings. Timely screening of pregnant women helps in the early diagnosis and management of complications related to thyroid disorders.

Study of thyroid function in pregnancy, its feto-maternal outcome; a prospective observational study

Background

Pregnancy is a stress test of maternal thyroid function. The prevalence of thyroid dysfunction in pregnant women is high. Subclinical hypothyroidism occurs in 10% of all pregnancies. Effects of hypothyroidism in pregnancy are anemia, low birth weight and mental retardation in neonate. This study is aimed to evaluate maternal and fetal outcomes in pregnant women with deranged thyroid profile. The relevance of this study is to document the association of hypothyroidism and its adverse effects on mother and fetus.

Methods

This prospective observational study was carried out at R.D. Gardi Medical College, Ujjain, India. Subjects of this study were 198 antenatal women in third trimester with singleton pregnancy admitted in the obstetric ward, and informed consent was obtained. Women were chosen irrespective of age, parity, residence and socioeconomic status. Women with multiple pregnancy, a known case of thyroid disorder, or any pre-existing medical disorder were excluded. Routine hematological parameters and estimation of T3, T4 and TSH was conducted. Patients with deranged thyroid profile were subsequently assessed for maternal and fetal complications. History of infertility, family history of thyroid disease, menstrual pattern, recurrent abortion, hemoglobin level and fetal outcome were the main study variables. Data was analysed in SPSS software for statistical co-relation.

Results

Prevalence of thyroid disorder is 11%; with subclinical hypothyroidism, overt hypothyroidism and subclinical hyperthyroidism occurring in 5.6, 3.5 and 1.5% of subjects respectively. In women with subclinical and overt hypothyroidism, anemia was present in 26.3% being significantly associated with hypothyroidism (p = 0.008). With respect to fetal outcome, LBW 31.6% (p = 0.001), NICU admission 42.1%, (p = 0.000) and low APGAR Score (21.1%, p = 0.042) were statistically associated with hypothyroidism. Risk of anemia, Low Birth weight, NICU admissions, and low APGAR score was 4.8, 6.3, 0.14 and 3.64 times higher respectively in women with hypothyroidism than in women who are euthyroid.

Conclusion

Prevalence of subclinical hypothyroidism is 5.6% in 3rd trimester of pregnancy. Anemia, pre-eclampsia, high caesarean rates and neonatal morbidities is significantly associated with hypothyroidism.

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.

Effects of maternal hypothyroidism in the gastrointestinal system of male young offspring from Wistar rats

Alterations in the maternal environment may impact on the fetal development. The objective of this study was to investigate the gastrointestinal consequences of maternal hypothyroidism for the male offspring from Wistar rats. The pregnant rats were divided into three groups: control (C - received water), experimental 1 [E1 - received methimazole (MMI) solution] during gestation and lactation, and experimental 2 (E2 - received MMI solution) during gestation. Maternal parameters evaluated: free T3 and T4, bodyweight variation, and water/food intake. Offspring parameters evaluated: litter size, number of male/female, free T3 and T4, stomach area, gastric ulcer susceptibility, small intestine length and weight, small intestine and distal colon motility, the stomach and intestinal weight-body weight ratio (SW/BW-IW/BW), and the accumulation of intestinal fluid. Maternal T3 and T4 from E1 were decreased when compared to the other groups. There were no differences for maternal water/food intake and weight gain, litter size, and number of males and females. Regarding to offspring, free T3, SW/BW, IW/BW, and intestinal fluid accumulation were not different between the groups, but T4 was decreased in E1. However, 30-day-old pups from E1 and E2 were smaller with lower stomach and small intestine. Even more, E1 presented a lower ulcer index when compared to the C, while E2 had a higher distal colon transit. It can be concluded that maternal hypothyroidism impaired the total body development, as well as gastric and intestinal development, besides interfering with the susceptibility to the ulcer and intestinal transit of male offspring from Wistar rats.

Maternal, cord, and three-year-old child serum thyroid hormone concentrations in the Health Outcomes and Measures of the Environment study

PURPOSE

Maternal thyroid function during pregnancy may influence offspring thyroid function, though relations between maternal and child thyroid function are incompletely understood. We sought to characterize relations between maternal, cord and child thyroid hormone concentrations in a population of mother-child pairs with largely normal thyroid function.

METHODS

In a prospective birth cohort, we measured thyroid hormone concentrations in 203 mothers at 16 gestational weeks, 273 newborns and 159 children at 3 years among participants in the Health Outcomes and Measures of the Environment (HOME) Study. We used multivariable linear regression to estimate associations of maternal thyroid hormones during pregnancy with cord serum thyroid hormones and also estimated associations of maternal and cord thyroid hormones with child thyroid-stimulating hormone (TSH).

RESULTS

Each doubling of maternal TSH was associated with a 16.4% increase of newborn TSH (95% CI: 3.9%, 30.5%), and each doubling of newborn TSH concentrations was associated with a 10.4% increase in child TSH concentrations at 3 years (95% CI: 0.1%, 21.7%). An interquartile range increase in cord FT4 concentrations was associated with an 11.7% decrease in child TSH concentrations at 3 years (95% CI: -20.2%, -2.3%).

CONCLUSIONS

We observed relationships between maternal, newborn and child thyroid hormone concentrations in the HOME Study. Our study contributes to understandings of interindividual variability in thyroid function among mother-child pairs, which may inform future efforts to identify risk factors for thyroid disorders or thyroid-related health outcomes.

Study on subclinical hypothyroidism in pregnancy: a bibliometric analysis via CiteSpace

Background: Subclinical hypothyroidism (SCH) in pregnancy has drawn an increasing amount of attention over the past two decades. However, the definition of it, including its clinical diagnosis and treatment, is still being revised. An increased risk of adverse pregnancy outcomes have been shown in most but not all studies. The objective of this study was to evaluate the origin, current trend and research hotspots on SCH in pregnancy.Methods: We obtained 630 records with 12,033 references, published between 1999 and 2018, from the online version of SCI-Expanded, Thomson Reuters Web of Science. The CiteSpace 5.3.R4 was used to perform the cooperation network analysis, key words co-occurrence and burst detection analysis, and reference cocitation analysis.Results: We identified that the number of publications on SCH in pregnancy was increasing over the past two decades. Teng WP and Shan ZY from the First Hospital of China Medical University, Shenyang, China, were found to be the most productive researchers in this field. USA was the leading country for publications. Subclinical hypothyroidism, pregnancy, hypothyroidism, dysfunction, disease, management, women, deficiency, association and hyperthyroidism were the top 10 high frequency keywords in all recruit documents. Follow up was the most strength burst key word in this field from 1999 through 2018, followed by maternal hypothyroxinemia, child, hypothyroidism complicating pregnancy, antithyroid antibody and fetal. Moreover, cocitation reference analysis revealed the top landmark articles and clusters in this field.Conclusion: This study provides the trends and frontiers in the field of SCH in pregnancy and valuable information for endocrine and/or obstetric researchers to identify new perspectives on potential collaborators and cooperative countries.

Exposure to Bisphenol A Analogs and the Thyroid Function and Volume in Women of Reproductive Age-Cross-Sectional Study

Bisphenols (BPs) are commonly known plastifiers that are widely used in industry. The knowledge about the impact of BPs on thyroid function is scarce. Proper thyroid functioning is especially important for women of reproductive age, as hypothyroidism affects fertility, pregnancy outcomes and the offspring. There are no studies analyzing the influence of BPs on thyroid function and volume in non-pregnant young women. The aim of this cross-sectional study was to evaluate the relationship between bisphenol A and its 10 analogs (BPS, BPC, BPE, BPF, BPG, BPM, BPP, BPZ, BPFL, and BPBP) on thyroid function and volume in women of reproductive age. Inclusion criteria were: female sex, age 18-40 years. Exclusion criteria were history of any thyroid disease, pharmacotherapy influencing thyroid function, pregnancy or puerperium, and diagnosis of autoimmune thyroid disease during this study. Venous blood was drawn for measurement of thyrotropin (TSH), free thyroxine, thyroid peroxidase antibodies, thyroglobulin antibodies, BPs. Urine samples were analyzed for: ioduria and BPs. Ultrasound examination of thyroid gland was performed. One hundred eighty participants were included into the study. A negative correlation was found between urine BPC and the thyroid volume (R = -0.258; p = 0.0005). Patients with detected urine BPC presented smaller thyroid glands than those with not-detected urine BPC (p = 0.0008). A positive correlation was found between TSH and urine BPC (R = 0.228; p = 0.002). Patients with detected urine BPC presented higher concentrations of TSH versus those with not-detected urine BPC (p = 0.003). There were no relationships between any of serum BPs as well as the other urine BPs and thyroid function and its volume. The only BP that demonstrated the relationship between thyroid function and its volume was BPC, probably because of its chemical structure that most resembles thyroxine. Exposure to this BP may result in the development of hypothyroidism that could have a negative impact on pregnancy and the offspring.

Effect of Gestational Weight Gain on Associations Between Maternal Thyroid Hormones and Birth Outcomes

Purpose: The aim was to investigate the associations between maternal thyroid parameters within the normal ranges during early pregnancy and birth outcomes, and further to examine whether the associations were modified by gestational weight gain (GWG). Methods: Maternal serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) concentrations within the normal ranges during early pregnancy were measured from 8,107 pregnant women in Wuhan, China. The associations between maternal thyroid parameters and birth outcomes (birth weight, birth length, and low birth weight) were analyzed using multivariable adjusted regression models, and effect modification by pre-pregnancy body mass index (BMI) category and GWG were further evaluated. Results: Maternal TSH and FT4 concentrations were negatively associated with birth weight, and the latter only occurred in normal weigh women with inadequate and excessive GWG, as well as in both underweight and overweight women with excessive GWG (e.g., β = -359.33 g, 95% CI: -700.95, -17.72 in underweight women with excessive GWG for per unit increase of FT4 concentrations). Moreover, maternal FT4 and FT3 concentrations were associated with increased risk for low birth weight, and the latter only occurred in normal weigh women with inadequate GWG (OR = 2.52, 95% CI: 1.00, 6.36 for per unit increase of FT3 concentrations). These associations still persist when maternal thyroid parameters were modeled as quintiles. Main conclusion: Maternal normal thyroid function during early pregnancy with excessive and inadequate GWG may adversely influence fetal growth.

Thyroid-Stimulating Hormone Values in Pregnancy: Cutoff Controversy Continues?

Thyroid disorders in pregnancy are important causes of adverse pregnancy outcome. So it is very pertinent that thyroid function is maintained in normal range during pregnancy. Serum thyroid-stimulating hormone (TSH) value is the best indicator for assessing and monitoring thyroid function. The increasing metabolic demands of pregnancy alter the thyroid physiology in early pregnancy; hence, it becomes necessary to define trimester-specific reference range. Several reports and guidelines have been published recommending varied TSH cutoffs in different studies. The most significant guidelines which created controversy about TSH cutoffs was that of American Thyroid Association (ATA) (Stagnaro-Green et al. in Thyroid 21:1081-1125, 2011) followed by Endocrine Society clinical practice guideline (De Groot et al. in J Clin Endocrinol 97:2543-2565, 2012). Both these gave stricter TSH cutoffs as .1 to 2.5 mIU/L in first trimester, .2 to 3.0 mIU/L in second trimester and .3 to 3 mIU/L in third trimester. Subsequently many reports, meta-analysis and systematic reviews were published which recommended higher cutoffs. With due consideration, ATA revised the guidelines in 2017, recommending the upper cutoff limit .5 mIU/L less than the preconception TSH value or as 4.0 mIU/L when local population-specific reference range is not available (Alexander et al. Thyroid 27(3):315-389, 2017). The controversy is not yet completely resolved specially regarding management of subclinical hypothyroidism. This editorial addresses this ongoing controversy.

Maternal TSH levels at first trimester and subsequent spontaneous miscarriage: a nested case-control study

Thyroid dysfunction is a frequently found endocrine disorder among reproductively aged women. Subclinical hypothyroidism is the most common condition of thyroid disorders during pregnancy and is defined as manifesting a thyroid-stimulating hormone concentration exceeding the trimester-specific reference value, with a normal free thyroxine concentration. Here, we evaluated the prospective association between spontaneous miscarriage and first-trimester thyroid function. We conducted a case-control study (421 cases and 1684 controls) that was nested. Thyroid-stimulating hormone (TSH), free thyroxine (FT4), thyroid-peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb) status were measured. We found that higher TSH was related to spontaneous miscarriage (OR 1.21; 95% CI, 1.13-1.30, P < 0.001). Compared with women with TSH levels of 0.4-<2.5 mIU/L, the risk of miscarriage was increased in women with TSH levels of 2.5-<4.87 mIU/L (OR 1.47; 95% CI, 1.16-1.87) and TSH greater than 4.87 mIU/L (OR 1.97; 95% CI, 1.22-3.18). After controlling for the confounding factor, TPOAb positivity status and FT4, the results were similar. The present study showed that higher TSH was associated with miscarriage in early pregnancy. In fact, TSH levels between 2.5 and 4.87 mIU/L increased the risk for miscarriage, with TSH greater than 4.87 mIU/L increasing the risk even further.

Perfluoroalkyl and polyfluoroalkyl substances and fetal thyroid hormone levels in umbilical cord blood among newborns by prelabor caesarean delivery

BACKGROUND

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) have been reported to disrupt the thyroid function. But epidemiological evidence on the association between PFAS and thyroid hormone (TH) levels in cord blood is scarce and controversial. We aimed to examine the association between cord blood PFAS concentrations and TH levels in prelabor caesarean deliveries.

METHODS

We measured ten PFAS and three THs in cord blood in 568 prelabor caesarean deliveries. The associations between PFAS and TH levels were examined using multiple linear regression model and sparse partial least squares (SPLS) regression model.

RESULTS

In SPLS analyses, thyroid stimulating hormone (TSH) level decreased with increasing concentrations of perfluorooctane sulfonate (PFOS, β = -0.012, 95% confidence interval [CI]: -0.019, -0.005), perfluorononanoic acid (PFNA, β = -0.012, 95% CI: -0.019, -0.005), perfluorodecanoic acid (PFDA, β = -0.012, 95% CI: -0.02, -0.005), perfluoroundecanoic acid (PFUA, β = -0.013, 95% CI: -0.021, -0.006) and perfluorododecanoic acid (PFDoA, β = -0.013, 95% CI: -0.023, -0.006). Moreover, we found a positive association between PFDoA and free thyroxine (FT4) levels (β = 0.190, 95% CI: 0.063, 0.304) after adjusting for potential confounders. Free tri-iodothyronine (FT3) levels were positively associated with concentrations of PFOS (β = 0.059, 95% CI: 0.023, 0.100), but negatively associated with PFDoA (β = -0.153, 95% CI: -0.212, -0.106). We also observed gender disparity in the associations of PFAS exposure and FT3, FT4, TSH levels.

CONCLUSION

Our results suggest that prenatal exposure to certain PFAS may disrupt fetal thyroid function. The effect may be gender-specific.

MATERNAL THYROID-STIMULATING HORMONE LEVEL IN THE FIRST TRIMESTER AND SEX RATIO AT BIRTH

Objective: Few studies have explored the influence of thyroid status on sex ratio at birth, and conclusions are inconsistent. The aim of this study was to determine if there is an association between serum thyroid-stimulating hormone (TSH) level in first trimester and sex ratio at birth. Methods: The study was a retrospective cohort study performed at a tertiary care center. From March 2014 to February 2017, a total of 4,822 women who had thyroid function testing during the first trimester were included. Study population was divided into five groups according to quintile of TSH level (≤0.60 mIU/L; 0.61 to 1.02 mIU/L; 1.03 to 1.44 mIU/L; 1.45 to 2.13 mIU/L; and ≥2.14 mIU/L). Logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of the percentage of male infants across the quintiles, with the lowest quintile as the reference category. Results: Median level of TSH was 1.27 mIU/L in women who delivered a boy, which was significantly higher than that in women who delivered a girl (1.15 mIU/L). After adjusting for age, gravidity, and parity, multivariate logistic analysis found that women in quintiles 3, 4, and 5 all showed significantly higher ORs for delivering a boy than those in quintile 1. In addition, after adjusting for age, gravidity, and parity, serum TSH was significantly associated with likelihood of having a boy (OR, 1.08; 95% CI, 1.03 to 1.13). Conclusion: Maternal TSH level in the first trimester is positively associated with the probability of delivering a male newborn. Abbreviations: CI = confidence interval; FT3 = free triiodothyronine; FT4 = free thyroxine; OR = odd ratio; SRB = sex ratio at birth; TBG = thyroxin-binding globulin; TSH = thyroid-stimulating hormone.

Management of Endocrinopathies in Pregnancy: A Review of Current Evidence

Pregnancy in women with associated endocrine conditions is a therapeutic challenge for clinicians. These disorders may be common, such us thyroid disorders and diabetes, or rare, including adrenal and parathyroid disease and pituitary dysfunction. With the development of assisted reproductive techniques, the number of pregnancies with these conditions has increased. It is necessary to recognize symptoms and correct diagnosis for a proper pharmacotherapeutic management in order to avoid adverse side effects both in mother and fetus. This review summarizes the pharmacotherapy of these clinical situations in order to reduce maternal and fetal morbidity.

Thyroid function in neonates of women with subclinical hypothyroidism or hypothyroxinemia

OBJECTIVE

To assess whether treatment of pregnant women with subclinical hypothyroidism or hypothyroxinemia alters neonatal TSH results.

STUDY DESIGN

A planned secondary analysis of data from two multi-center randomized, double-masked, placebo-controlled thyroxine replacement trials in pregnant women with either subclinical hypothyroidism or hypothyroxinemia. Infant heel-stick specimens were obtained before discharge. We compared TSH levels between neonates born to mothers allocated to treatment or placebo within each trial and between neonates in the placebo groups. Multiples of means were generated for day-of-life-specific data.

RESULTS

Neonatal TSH values were available for 573/677 (84.6%) newborns from the subclinical hypothyroidism trial and 461/526 (87.6%) newborns from the hypothyroxinemia trial. Neonatal TSH values did not differ in either trial by treatment group or between placebo groups (P > 0.05 for all comparisons).

CONCLUSIONS

Neonatal TSH values did not differ with thyroid hormone replacement in pregnancies diagnosed with subclinical hypothyroidism or hypothyroxinemia.

Chronic diseases in the children of women with maternal thyroid dysfunction: a nationwide cohort study

Objective

Maternal thyroid disease (TD) during pregnancy is associated with adverse birth outcomes, but little is known on its long-term outcomes. We aimed to examine if children born to mothers with TD have increased disease risk during childhood and adolescence.

Patients and methods

A register-based cohort study was conducted on all live born children in Denmark from 1989 to 2013, including the association between maternal TD during pregnancy and somatic and psychiatric diseases in the children. Cox proportional hazards models were used to compute hazard ratios (HRs) according to the type of maternal TD, Graves’ disease, and Hashimoto’s thyroiditis.

Results

A total of 2,618 children were born to women with Graves’ disease, 760 to women with Hashimoto’s thyroiditis (exposed), and 1,557,577 to women without any TD (unexposed). The median follow-up time for children born to mothers with Graves’ disease was 9.3 years (25/75 percentile 5.4/13.9 years) and with Hashimoto’s thyroiditis was 4.8 years (25/75 percentile 2.5/8.2 years). In children exposed to maternal Graves’ disease in utero, the adjusted HR of TD was 12.83 (95% CI, 9.74–16.90), Graves’ disease was 34.3 (95% CI, 20.23–58.35), and type 1 was diabetes 2.47 (95% CI, 1.46–4.18). In children exposed to maternal Hashimoto’s thyroiditis, the adjusted HR of Hashimoto’s thyroiditis was 24.04 (95% CI, 5.89–97.94).

Conclusion

Our data suggest that children born to women with Graves’ disease and Hashimoto’s thyroiditis have excess long-term morbidities in childhood and adolescence. We particularly found an increased risk of any TD and type 1 diabetes to be diagnosed in children exposed in utero to Graves’ disease. These novel findings are relevant for pediatricians, stressing the importance of history of maternal disease when evaluating children with suspected endocrine disorders.

Effect of maternal hypothyroidism during pregnancy on insulin resistance, lipid accumulation, and mitochondrial dysfunction in skeletal muscle of fetal rats

The present study aimed to investigate the effect of maternal hypothyroidism during pregnancy on thyroid function of the fetal rat. Female Sprague–Dawley rats were randomized into two groups. Propylthiouracil (PTU) group received PTU in drinking water for 6 weeks (n=90), normal group received normal drinking water (n=50). The pregnant rats were obtained and had a cesarean-section to get at gestational ages of 8.5, 13, and 21 days, following blood samples and skeletal muscle were obtained from fetal rats. Levels of thyroid hormone, insulin, mitochondrial protein, and adipokines were detected using ELISA. Western blotting was performed to analyze mitochondria and insulin signal transduction-related protein in fetal rat skeletal muscle. Immunostaining of Periodic Acid-Schiff (PAS) and Oil Red O was used to observe the accumulation of muscle glycogen and lipid in the fetal rat. The results showed that the levels of thyroid hormone, insulin, insulin signal transduction-related protein, mitochondrial, and adipokines increased with the fetus developed, but had no statistical differences in the PTU group compared with the normal group. In conclusion, pregnant rats with hypothyroidism had no influence on insulin resistance (IR), lipid accumulation, and mitochondrial dysfunction in skeletal muscle of the fetal rats.

The Association Between Maternal Subclinical Hypothyroidism and Growth, Development, and Childhood Intelligence: A Meta-analysis

OBJECTIVE

To explore the association between maternal subclinical hypothyroidism (SCH) in pregnancy and the somatic and intellectual development of their offspring.

METHODS

Using RevMan 5.3 software, a meta-analysis of cohort studies published from inception to May 2017, focusing on the association between maternal SCH in pregnancy and childhood growth, development and intelligence, was performed. Sources included the Cochrane Library, Pub-Med, Web of Science, China National Knowledge Infrastructure and Wan Fang Data.

RESULTS

Analysis of a total of 15 cohort studies involving 1.896 pregnant women with SCH revealed that SCH in pregnancy was significantly associated with the intelligence (p=0.0007) and motor development (p<0.00001) of the offspring. SCH was also significantly associated with the child’s weight in four studies involving 222 women (p=0.02). Maternal SCH in pregnancy was identified as a risk factor for fetal growth restriction with a combined relative risk (RR) value of 2.4 [95% confidence interval (CI): 1.56, 3.7]. Meta-analysis of 10 studies that provided numbers of preterm infants revealed a significant association between maternal SCH in pregnancy and premature delivery, with a combined RR of 1.96 (95% CI: 1.34, 2.88). There was a significant effect of maternal SCH in pregnancy on fetal distress in utero (p=0.003).

CONCLUSION

Maternal SCH in pregnancy is associated with increased risk of adverse neonatal outcomes, including delayed intellectual and motor development, low birth weight, premature delivery, fetal distress and fetal growth restriction.

Effect of hypothyroidism on the hypothalamic-pituitary-ovarian axis and reproductive function of pregnant rats

BACKGROUND

This study aimed to detect changes in hormone levels in the hypothalamic-pituitary-ovarian axis in Sprague-Dawley (SD) rats with hypothyroidism, and identify differences in the pregnancy and abortion rates of female adult rats. The potential role of gonadotropin releasing hormone (GnRH) as the link between the hypothalamic-pituitary-ovarian axis and reproductive function regulated by thyroid hormones was also investigated.

METHODS

Female SD rats (n = 136) were causally classified into two groups: the normal-drinking-water group (n = 60) and the 0.05% propylthiouracil-drinking-water group (PTU 2 mg/kg/day, n = 76) to establish an adult rat model of hypothyroidism (6 weeks). Female and male rats at a ratio of 1:2 were used to establish a hypothyroidism pregnancy model. GnRH mRNA and GnRH receptor (GnRHR) expression in rats was detected using real time quantitative PCR(qRT-PCR) and immunohistochemistry, respectively.

RESULTS

The abortion rate differed significantly between the hypothyroidism pregnancy group and the normal pregnancy group (P < 0.05). No significant differences were found in the distribution of the GnRHR among the five nuclei (hypothalamic arcuate nucleus, hypothalamic ventromedial nucleus, hypothalamic anterior nucleus, paraventricular nucleus of the hypothalamus, and ventral premammillary nucleus) of the hypothalamus and ovary (P > 0.05). Hypothyroidism had no significant effect on GnRH mRNA expression in the hypothalamic-pituitary-ovarian axis in the four groups (normal control group, normal pregnancy group, hypothyroidism pregnancy group, and hypothyroidism group) (P > 0.05).

CONCLUSIONS

Hypothyroidism had an adverse impact on pregnancy in rats and may affect the distribution of pituitary GnRHR, whereas it did not obviously affect the distribution of GnRHR in the nuclei of the hypothalamus and ovary. Hypothyroidism had no effect on GnRH mRNA expression.

Maternal urinary phthalate metabolites during pregnancy and thyroid hormone concentrations in maternal and cord sera: The HOME Study

BACKGROUND

Phthalates, endocrine-disrupting chemicals that are commonly found in consumer products, may adversely affect thyroid hormones, but findings from prior epidemiologic studies are inconsistent.

OBJECTIVES

In a prospective cohort study, we investigated whether maternal urinary phthalate metabolite concentrations and phthalate mixtures measured during pregnancy were associated with thyroid hormones among pregnant women and newborns.

METHODS

We measured nine phthalate metabolites [monoethyl phthalate (MEP), mono-n-butyl phthalate, mono-isobutyl phthalate, monobenzyl phthalate (MBzP), and four monoesthers of di(2-ethylhexyl) phthalate] in urine collected at approximately 16 and 26 weeks' gestation among women in the Health Outcomes and Measures of the Environment Study (2003-2006, Cincinnati, Ohio). Thyroid stimulating hormone (TSH) and free and total thyroxine and triiodothyronine were measured in maternal serum at 16 weeks' gestation (n = 202) and cord serum at delivery (n = 276). We used multivariable linear regression to assess associations between individual urinary phthalate metabolites and concentrations of maternal or cord serum thyroid hormones. We used weighted quantile sum regression (WQS) to create a phthalate index describing combined concentrations of phthalate metabolites and to investigate associations of the phthalate index with individual thyroid hormones.

RESULTS

With each 10-fold increase in 16-week maternal urinary MEP, maternal serum total thyroxine (TT₄) decreased by 0.52 μg/dL (95% CI: -1.01, -0.03). For each 10-fold increase in average (16- and 26-week) maternal urinary MBzP, cord serum TSH decreased by 19% (95% CI: -33.1, -1.9). Among mothers, the phthalate index was inversely associated with maternal serum TT₄ (WQS beta = -0.60; 95% CI: -1.01, -0.18). Among newborns, the phthalate index was inversely associated with both cord serum TSH (WQS beta = -0.11; 95% CI: -0.20, -0.03) and TT₄ (WQS beta = -0.53; 95% CI: -0.90, -0.16).

CONCLUSION

Our results suggest that co-exposure to multiple phthalates was inversely associated with certain thyroid hormones (TT₄ in pregnant women and newborns, and TSH in newborns) in this birth cohort. These findings highlight the need to study chemical mixtures in environmental epidemiology.

Prevalence of Hypothyroidism in Term Pregnancies in North India

BACKGROUND

Hypothyroidism is common in pregnancy. No study has determined the prevalence of hypothyroidism in term pregnancies in India.

AIM

This study aims to determine the prevalence and correlates of hypothyroidism in women who delivered at a center in Karnal, Haryana, North India.

RESULTS

Indoor records of all women who had delivered at this centre from April 2016 to March 2017 were reviewed. The prevalence of hypothyroidism was 12.3%, of which 15.5% were diagnosed during pregnancy. The dose requirement of L-thyroxine ranged from 25 to 200 μg (mean 76.38 +- 43.02). With this, 80% were able to achieve trimester-specific thyroid-stimulating hormone targets. Hypothyroidism did not correlate with any medical or obstetric complications.

CONCLUSION

Hypothyroidism is common in term pregnancies. If treated adequately, healthy fetomaternal outcomes can be achieved.

The relation of maternal hypothyroidism and hypothyroxinemia during pregnancy on preterm birth: An updated systematic review and meta-analysis

BACKGROUND

The clinical consequences of hypothyroidism and hypothyroxinemia during pregnancy such as preterm birth are not still clear.

OBJECTIVE

The aim of this meta-analysis was to estimate the relation of clinical and subclinical hypothyroidism and hypothyroxinemia during pregnancy and preterm birth.

MATERIALS AND METHODS

In this meta-analysis, Preferred Reporting Items for Systematic review and Meta-Analysis were utilized. Searching the cohort studies were done by two researchers independently without any restrictions on Scopus, PubMed, Science Direct, Embase, Web of Science, CINAHL, Cochrane, EBSCO and Google Scholar databases up to 2017. The heterogeneity of the studies was checked by the Cochran's Q test and I2 index. Both random and fixed-effects models were used for combining the relative risk and 95% confidence intervals. Data were analyzed using Comprehensive Meta-Analysis software version 2.

RESULTS

Twenty-three studies were included in the meta-analysis. The relative risks of the clinical hypothyroidism, subclinical hypothyroidism and hypothyroxinemia during pregnancy on preterm birth was estimated 1.30 (95% CI: 1.05-1.61, p=0.013, involving 20079 cases and 2452817 controls), 1.36 (95% CI: 1.09-1.68, p=0.005, involving 3580 cases and 64885 controls) and 1.31 (95% CI: 1.04-1.66, p=0.020, involving 1078 cases and 44377 controls), respectively.

CONCLUSION

The incidence of preterm birth was higher among mothers with clinical and subclinical hypothyroidism or hypothyroxinemia during pregnancy compared to euthyroid mothers, and these relations were significant. Therefore, gynecologists and endocrinologists should manage these patients to control the incidence of adverse pregnancy outcomes such as preterm birth.

The debate on treating subclinical hypothyroidism

Subclinical hypothyroidism (SCH) represents a mild or compensated form of primary hypothyroidism. The diagnosis of SCH is controversial, as its symptoms are non-specific and its biochemical diagnosis is arbitrary. The treatment of SCH was examined among non-pregnant adults, pregnant adults and children. In non-pregnant adults, treatment of SCH may prevent its progression to overt hypothyroidism, reduce the occurrence of coronary heart disease, and improve neuropsychiatric and musculoskeletal symptoms associated with hypothyroidism. These benefits are counteracted by cardiovascular, neuropsychiatric and musculoskeletal side effects. SCH is associated with adverse maternal and fetal outcomes that may improve with treatment. Treating SCH in children is safe and may improve growth. Importantly, the evidence in this field is largely from retrospective and prospective studies with design limitations, which precludes a conclusive recommendation for the treatment of SCH.

The Treatment of Hypothyroidism in Pregnancy

Hypothyroidism is a pathologic condition generated by the thyroid hormone deficiency. The American Thyroid Association advises for the screening of hypothyroidism beginning at 35 years and thereafter every 5 years in people at high risk for this condition: females older than 60 years, pregnant women, patients with other autoimmune disease or patients with a history of neck irradiation. In pregnant women, hypothyroidism can been associated with adverse effect for both mother and child. The „Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum“ recommends the treatment of maternal overt hypothyroidism: females with a thyrotropin (TSH) level higher than the trimester-specific reference interval and decreased free thyroxine (FT4), and females for which TSH level is higher than 10.0 mIU/L, irrespective of the FT4 value, with administration of oral levothyroxine. The goal of treatment of maternal overt hypothyroidism is to bring back the serum TSH values to the reference range specific for the pregnancy trimester. The Guidelines of the „European Thyroid Association for the Management of Subclinical Hypothyroidism in Pregnancy and in Children“ recommends treatment of pregnancy associated subclinical hypothyroidism with the following levothyroxine doses: „1.20 μg/kg/day for TSH≤4.2 mU/l, 1.42 μg/kg/day for TSH >4.2-10 and 2.33 μg/kg/day for overt hypothyroidism“. The „Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum“ and the „European Thyroid Association for the Management of Subclinical Hypothyroidism in Pregnancy and in Children“ do not recommend the treatment of isolated hypothyroxinemia in pregnancy.

Patients with subclinical hypothyroidism before 20 weeks of pregnancy have a higher risk of miscarriage: A systematic review and meta-analysis

Objective

To evaluate the relationship between subclinical hypothyroidism (SCH) and the risk of miscarriage before 20 weeks of pregnancy.

Methods

Literature databases were searched, including the PubMed, Web of Science, Embase and Cochrane databases, from January 1, 1980, to December 31, 2015. The following search terms were used: subclinical hypothyroidism, hypothyroidism, thyroid dysfunction, thyroid hypofunction, subclinical thyroid disease, thyroid dysfunction, pregnancy loss, abortion and miscarriage. Studies comparing the prevalence of miscarriage in pregnant women with SCH with those who were euthyroid were selected. From the studies matched, the relative risk (RR) and corresponding 95% confidence interval (95% CI) were calculated to yield outcomes. All the statistical analyses were performed using Review Manager (Revman) Version 5.3 and Stata Version 12.0 software. The publication bias of the studies was assessed by forest plot and Begg’s test, while the stability of the results was evaluated by sensitivity analysis.

Results

Nine articles satisfying the inclusion criteria were analysed. Compared to euthyroid pregnant women, patients with non-treated SCH had a higher prevalence of miscarriage (RR = 1.90, 95% CI1.59–2.27, P<0.01). Additionally, SCH patients in the international diagnostic criteria group were more likely to suffer miscarriages than those in the ATA diagnostic criteria group (χ² = 11.493, P<0.01). Moreover, there was no difference between patients with treated SCH and euthyroid women (RR = 1.14, 95% CI0.82–1.58, P = 0.43). Compared to isolated SCH women, the miscarriage risk of SCH patients with thyroid autoimmunity (TAI) was obviously higher (RR = 2.47, 95% CI1.77–3.45, P<0.01), and isolated SCH patients also had a higher prevalence of miscarriages than euthyroid women (RR = 1.45, 95% CI1.07–1.96, P = 0.02).A heterogeneity test, forest plot and Begg’s test suggested that there was no significant heterogeneity or publication bias among the included articles, while the result of sensitivity analysis showed that our study exhibited high stability.

Conclusion

SCH is a risk factor for miscarriage in women before 20 weeks of pregnancy, and early treatments can reduce the miscarriage rate. Regardless of the diagnostic criteria used, the miscarriage rate increased as long as a pregnant woman was confirmed to have SCH. The results show that the omission diagnostic rate may increase when the ATA diagnostic criteria are used. In addition, SCH patients with TAI have a higher prevalence of miscarriage, while isolated SCH patients also have a higher miscarriage rate than euthyroid women. Thus, we recommend early treatments to avoid adverse pregnancy outcomes and complications.

Benign thyroid disease in pregnancy: A state of the art review

Thyroid dysfunction is the commonest endocrine disorder in pregnancy apart from diabetes. Thyroid hormones are essential for fetal brain development in the embryonic phase. Maternal thyroid dysfunction during pregnancy may have significant adverse maternal and fetal outcomes such as preterm delivery, preeclampsia, miscarriage and low birth weight. In this review we discuss the effect of thyroid disease on pregnancy and the current evidence on the management of different thyroid conditions in pregnancy and postpartum to improve fetal and neonatal outcomes, with special reference to existing guidelines on the topic which we dissect, critique and compare with each other. Overt hypothyroidism and hyperthyroidism should be treated appropriately in pregnancy, aiming to maintain euthyroidism. Subclinical hypothyroidism is often pragmatically treated with levothyroxine, although it has not been definitively proven whether this alters maternal or fetal outcomes. Subclinical hyperthyroidism does not usually require treatment and the possibility of non-thyroidal illness or gestational thyrotoxicosis should be considered. Autoimmune thyroid diseases tend to improve during pregnancy but commonly flare-up or emerge in the post-partum period. Accordingly, thyroid auto-antibodies tend to decrease with pregnancy progression. Postpartum thyroiditis should be managed based on the clinical symptoms rather than abnormal biochemical results.

Thyroid Hormone Status in Umbilical Cord Serum Is Positively Associated with Male Anogenital Distance

CONTEXT

In human adults and adolescents, thyroid function affects sex hormones and male reproductive functions. Little is known about the thyroid function effects on the gonadal development in human infants.

OBJECTIVE

The aim was to examine the association between thyroid hormones (THs) and sexually dimorphic genital development or fetal growth.

DESIGN

This is a birth cohort study.

PARTICIPANTS

A total of 616 mothers and newborns were analyzed from two local hospitals.

MAIN OUTCOME MEASURES

TSH, free T3 (FT3), and free T4 (FT4) levels in cord blood serum, anogenital distance (AGD), birth weight, birth length, birth body mass index, and head circumference in neonates.

RESULTS

Longer AGD in male newborns was observed with higher cord serum FT3 (β, 1.36 mm [95% confidence interval (CI), 0.58-2.13] for 1 pmol/L FT3), FT4 (β, 0.12 mm [95% CI, 0.00-0.25] for 1 pmol/L FT4), and TSH (β, 3.14 mm [95% CI, 0.65-5.63] for a 10-fold TSH increase), and with a lower FT4/FT3 ratio (β, -0.11 mm [95% CI, -0.20 to -0.02] for doubling FT4/FT3 ratio). The relationships between TSH, birth weight, and birth length were different by secondhand smoke exposure. Secondhand smoke exposure had an effect modification, with interaction P value .039 and .010, respectively. Secondhand smoke exposure also had an effect modification on the relation between FT4 and head circumference with interaction P value .020.

CONCLUSIONS

In the absence of overt thyroid dysfunction, THs are positively associated with AGD in male newborns. TH effects on body size and head circumference may be modified by maternal secondhand smoke exposure.

Unusual Presentation of Hypothyroidism in a Pregnant Woman, Mimicking Gestational Trophoblastic Neoplasm

Hypothyroidism is a common health issue worldwide with varying clinical manifestations. We report a woman who experienced an incomplete abortion and undiagnosed hypothyroidism who was referred to the oncologist with the suspicion of metastatic gestational trophoblastic neoplasm (GTN). A 29-year-old woman with incomplete abortion was referred to an oncologist for possible GTN due to persistent active vaginal bleeding, an elevated beta human chorionic gonadotropin (hCG), abnormal cervical inspection exam, abnormal liver function tests, ovarian enlargement, ascites, and a pleural effusion. She was found to have hypothyroidism in further work-up. She was managed with thyroid hormone replacement therapy and her condition improved after 6 weeks. Complete resolution of the ovarian mass and pericardial and pleural effusion was achieved. This case describes an important experience; hypothyroidism should be considered in the differential diagnosis of any woman with an incomplete abortion presenting with an ovarian mass. Evaluation and correct diagnosis are important to prevent mismanagement.