Thyroid diseases and adverse pregnancy outcomes in a contemporary US cohort

The construction and validation of a prediction model of hypertensive disease in pregnancy

The HDP prediction model was constructed and validated by using the demographic characteristics, blood routine and biochemical screening indicators in early pregnancy to reduce the incidence of HDP. 16,112 pregnant women admitted to Yuyao People's Hospital from May 1, 2018 to April 30, 2022 were randomly divided into modeling group (n = 11279) and validation group (n = 4833) according to a ratio of 7:3. Demographic characteristics, blood routine and biochemical screening data of 8-12+ 6 weeks gestation were obtained from Ningbo Health Records system. Univariate analysis and multivariate binary Logistic regression analysis were used to determine the independent risk factors of HDP, and the scoring system was established by using the nomogram. Univariate analysis and multivariate binary Logistic regression analysis showed that Age, BMI, previous medical history, HB, TG, HDL and ALB were independent risk factors for HDP (P < 0.001). In the modeling group, AUC = 0.809, sensitivity = 74.30%, specificity = 73.10%, and in the validation group, AUC = 0.801, sensitivity = 77.60%, specificity = 68.90%. Hosmer-Lemeshow goodness of fit test showed that modeling group: P = 0.195 > 0.05, validation group: P = 0.775 > 0.05. The prediction model of early pregnancy Age, BMI, previous medical history, HB, TG, HDL and ALB can effectively predict the occurrence of HDP.

Association between levothyroxine supplementation for hypothyroidism in late pregnancy and risk of prematurity: a population-based cohort study

BACKGROUND

Hypothyroidism in pregnancy is associated with obstetrical and fetal complications, such as prematurity. However, whether its management by levothyroxine affects the risk of prematurity is not yet clear.

METHODS

We conducted a cohort study within the Quebec Pregnancy Cohort including pregnancies with hypothyroidism from January 1, 1998, through December 31, 2015. In primary analyses, we considered levothyroxine exposure (yes/no), total duration, mean daily dose, and cumulative dose in the 2-months period before delivery (for preterm deliveries) or before 37th weeks' gestation (for term deliveries). Secondly, levothyroxine dosage before and after the beginning of the second trimester were compared, and pregnancies were categorized in increased or constant dosage groups. Lastly, levothyroxine was also defined as a time-varying daily exposure from the 14th weeks' gestation until delivery or 37th weeks' gestation, whichever came first. Prematurity was defined as giving birth before the 37th weeks' gestation. Term pregnancies were censored at 37th weeks' gestation because they were no longer at risk of prematurity afterwards. Generalized estimating equations and Cox-proportional hazard models, adjusted for potential confounders, were used to calculate adjusted relative risks (aRRs) and hazard ratios (aHRs), respectively.

RESULTS

A total of 9489 pregnant individuals with hypothyroidism were included. Among them, 6667 (70.3%) were exposed to levothyroxine in the 2-months time-window. Adjusting for potential confounders, no association was observed between levothyroxine exposure (aRR, 0.98; 95% CI, 0.81-1.20) and the risk of prematurity compared to non-exposed. Also, no association between levothyroxine duration (> 30 days: aRR, 0.99; 95% CI, 0.81-1.21), cumulative dose (> 7125 mcg: aRR, 0.97; 95% CI, 0.73-1.27) or mean daily dose (> 125 mcg/day: aRR, 0.95; 95% CI, 0.72-1.26) and the risk of prematurity was observed, compared to non-exposure. Finally, the risk of prematurity did not vary between increased or constant dosage groups (aRR, 0.84; 95% CI, 0.67-1.05). Similarly, time-varying exposure analysis did not show any association between levothyroxine exposure and prematurity risk (aHR, 0.95; 95% CI, 0.81-1.11).

CONCLUSIONS

Levothyroxine supplementation in late pregnancy among individuals with hypothyroidism was not associated with prematurity risk. Our findings support the safe use of levothyroxine during gestation and might be useful for the current guidelines.

Free Triiodothyronine Concentrations and Gestational Diabetes Mellitus: Unveiling the Correlation and Implications

Thyroid disease and gestational diabetes mellitus (GDM) are frequent complications during pregnancy. We observed the relationship between thyroid indicators and blood glucose to analyze whether thyroid function is associated with the development of GDM. We enrolled a total of 575 pregnant women diagnosed with GDM and 573 pregnant women without GDM. The correlation between thyroid indicators and blood glucose levels was established through correlation analysis. In addition, stratified analysis and restricted cubic spline curves were employed to describe the association between thyroid indicators and the incidence of GDM. We found no significant difference in urine iodine levels between the GDM and non-GDM groups throughout the second trimester. The levels of free triiodothyronine (FT3) and both fasting blood glucose and post-load blood glucose showed a robust positive connection. Thyroid-stimulating hormone (TSH) and free thyroxine (FT4), on the other hand, showed a weakly positive connection with these glucose values. A nonlinear correlation between FT3 and the risk of GDM was also found (pNonlinear=0.0007, p<0.0001). Particularly, those in the top quartile of FT3 had a 6.99-fold greater risk than those in the lowest. Notably, FT3 levels below 4.04 pmol/l were linked to a decreased chance of developing GDM, but levels over 4.04 pmol/l were linked to a greater risk. Our study successfully established the correlation between thyroid indicators and the risk of GDM. Notably, we discovered a non-linear association between FT3 levels and GDM. The study suggests that ensuring optimal thyroid function during pregnancy may decrease the likelihood of developing GDM.

Elevated Serum TSH Levels and TPOAb Positivity in Early Pregnancy are Associated with Increased Risk of Hypertensive Disorders of Pregnancy: A Prospective Cohort Study

Background: The relationship between maternal thyroid-stimulating hormone (TSH), free thyroxine (FT4) and thyroid peroxidase antibody (TPOAb) status and hypertensive disorders of pregnancy (HDP) remains uncertain. Methods: This was a prospective cohort study based on the China Birth Cohort Study (CBCS). 36,256 women were included at 6 to 13+6 gestation from February 2018 to December 2020. Generalized linear mixed models were used to investigate the association between thyroid function and HDP/BP. We further performed multiple subgroup analyses to test the robustness of this association. Results: The final study population was 25,608, and the overall incidence of HDP was 8.0%. After adjusting for maternal age, pre-pregnancy BMI, education, household annual income, smoking status, conception method and parity, the odds of HDP increased by 3.0% with a 1-unit increase in TSH (OR 1.03, 95% CI 1.04-1.06). Maternal TSH and TPOAb positivity were associated with a higher risk of preeclampsia or eclampsia but not gestational hypertension (TSH: OR 1.04, 95% CI 1.01-1.07; TPOAb positivity: OR 1.30, 95% CI 1.09-1.56). TSH and TPOAb positivity were significantly and positively associated with systolic pressure (TSH: β 0.02, 95% CI 0.07-0.26; TPOAb positivity: β 0.02, 95% CI 0.12-0.98) and diastolic pressure (TSH: β 0.02, 95% CI 0.02-0.17; TPOAb positivity: β 0.02, 95% CI 0.06-0.75). Subgroup analyses suggested that the association between TSH and diastolic pressure was stronger in those with BMI ≥ 25 kg/m2 (P = 0.014). Conclusions: Our founds suggest that high TSH and TPOAb positivity in the first trimester are associated with an increased risk of preeclampsia or eclampsia.

Subacute thyroiditis during pregnancy: clinical characteristics of seven cases

Objective

There are few reports of subacute thyroiditis (SAT) during pregnancy. This study aimed to clarify the clinical characteristics of SAT in pregnant patients.

Methods and results

Seven patients diagnosed with SAT during pregnancy at our institution from January 2004 to December 2021 were identified, and their clinical findings were retrospectively examined. At SAT diagnosis, the median age was 34 (range: 31-42) years, the median duration of pregnancy was 5 (4-24) weeks, and all patients had neck pain but no fever. On laboratory examination, median (range) free thyroxine, free triiodothyronine, and C-reactive protein levels were 2.66 (1.14-7.77) ng/dL, 7.1 (3.3-16.1) pg/mL, and 2.22 (0.42-5.79) mg/dL, respectively, and all patients had a hypoechoic lesion of the thyroid gland. Three patients (43%) were treated with steroids, and three patients (43%) received replacement therapy with levothyroxine for hypothyroidism following destructive thyroiditis. There were no pregnancy complications in any of the cases. These seven patients (pregnancy group) were compared with 217 non-pregnant female patients (non-pregnancy group) aged 31 to 42 years who were diagnosed with SAT at our institution from 2016 to 2019. The frequency of body temperatures above 37°C was lower in the pregnancy group than in the non-pregnancy group (0% vs 65%).

Conclusion

Patients who develop SAT during pregnancy may have less fever than non-pregnant patients with SAT. There were no pregnancy complications in the pregnancy group in this study. This suggests that adverse pregnancy outcomes may be avoided by the appropriate management of SAT, including hypothyroidism after destructive thyroiditis.

Iodine supply and thyroid function in women with gestational diabetes mellitus: a cohort study

Introduction

Maternal urinary iodine concentration and blood neonatal thyroid-stimulating hormone (TSH) concentration reflect iodine status in pregnancy and serve as markers of iodine deficiency. As dietary measures in gestational diabetes mellitus (GDM) could affect iodine intake, our study aimed to investigate iodine supply in women with GDM compared to healthy pregnant women and to evaluate its relationship to maternal and neonatal thyroid function.

Methods

Urinary iodine concentration (UIC) and serum TSH, free thyroxine (FT4), and autoantibodies against thyroid peroxidase (TPOAb) were analyzed in 195 women with GDM and 88 healthy pregnant women in the second trimester. Subsequently, neonatal TSH concentrations measured 72 h after delivery in a subgroup of 154 newborns (115 of mothers with GDM and 39 controls) from the national register were analyzed.

Results

Median UIC was significantly lower in women with GDM compared to controls (89.50 µg/L vs. 150.05 µg/L; P < 0.001). Optimal iodine intake was found only in nine women with GDM (4.6%) and 33 healthy pregnant women (37.5%) (P < 0.001). Most pregnant women with GDM (88.7%) compared to one half of controls (50%) had iodine deficiency (P < 0.001). Although serum TSH and the prevalence of hypothyroidism (TSH > 4.0 mIU/L) were not different in both groups, hypothyroxinaemia was more prevalent in GDM compared to controls (12.3% vs 3.4%, P = 0.032). Consistently, neonatal TSH > 5.0 mIU/L indicating iodine deficiency, was found in 6 (5.2%) newborns of women with GDM as compared to none in controls. In women with GDM, the prevalence of perinatal complications was significantly lower in those who were taking dietary iodine supplements compared to those who were not (3/39 (7.69%) vs 46/156 (28.85%), P <0.001). In the multiple logistic and linear regression models in women with GDM, hypothyroxinaemia was associated with preterm births, and a negative association of serum FT4 and HbA1c was found.

Conclusion

Iodine deficiency in pregnancy was more prevalent among women with GDM compared to healthy pregnant controls. Serum FT4 negatively correlated with HbA1c, and hypothyroxinaemia was associated with preterm births in women with GDM. Conversely, women with GDM who used dietary iodine supplements had a lower risk of perinatal complications.

Causal pathways in preeclampsia: a Mendelian randomization study in European populations

Purpose

Our study utilizes Mendelian Randomization (MR) to explore the causal relationships between a range of risk factors and preeclampsia, a major contributor to maternal and perinatal morbidity and mortality.

Methods

Employing the Inverse Variance Weighting (IVW) approach, we conducted a comprehensive multi-exposure MR study analyzing genetic variants linked to 25 risk factors including metabolic disorders, circulating lipid levels, immune and inflammatory responses, lifestyle choices, and bone metabolism. We applied rigorous statistical techniques such as sensitivity analyses, Cochran's Q test, MR Egger regression, funnel plots, and leave-one-out sensitivity analysis to address potential biases like pleiotropy and population stratification.

Results

Our analysis included 267,242 individuals, focusing on European ancestries and involving 2,355 patients with preeclampsia. We identified strong genetic associations linking increased preeclampsia risk with factors such as hyperthyroidism, BMI, type 2 diabetes, and elevated serum uric acid levels. Conversely, no significant causal links were found with gestational diabetes, total cholesterol, sleep duration, and bone mineral density, suggesting areas for further investigation. A notable finding was the causal relationship between systemic lupus erythematosus and increased preeclampsia risk, highlighting the significant role of immune and inflammatory responses.

Conclusion

This extensive MR study sheds light on the complex etiology of preeclampsia, underscoring the causal impact of specific metabolic, lipid, immune, lifestyle, and bone metabolism factors. Our findings advocate for a multidimensional approach to better understand and manage preeclampsia, paving the way for future research to develop targeted preventive and therapeutic strategies.

A Review of Autoimmune Thyroid Diseases and Their Complex Interplay with Female Fertility

Hashimoto thyroiditis and Graves' disease are autoimmune thyroid disorders that are common in women of reproductive age and have a complex relationship with female fertility and health of the maternal-fetal dyad. Both hyperthyroidism and hypothyroidism, whether subclinical or overt in severity, directly or indirectly affect nearly every level of the hypothalamic-pituitary-ovary axis, uterine and ovarian function, as well as fetal development from implantation through delivery. Autoimmunity itself also appears to negatively impact both spontaneous and assisted fertility, as well as miscarriage risk, although the mechanism remains unclear, and the presence and magnitude of risk is variable in published literature. While treatment of overt hyperthyroidism and hypothyroidism is unequivocally recommended by professional societies, the impact of treatment on fertility outcomes, and the role of treatment in subclinical thyroid disease is more controversial. Unfortunately, levothyroxine has not been shown to abrogate the risk of subfertility and miscarriage observed in euthyroid thyroid autoantibody positive women.

Overt hypothyroidism in pregnancy and language development in offspring: is there an association?

PURPOSE

Overt hypothyroidism during pregnancy is linked to various obstetric complications, such as premature birth and fetal death. While some studies have shown that maternal hypothyroidism can impact a child's Intelligence Quotient (IQ) and language development, findings are controversial. The aim of this study was to explore the connection between treated maternal hypothyroidism during pregnancy and offspring neurodevelopment, focusing on learning and language and examining related maternal obstetric complications.

METHODS

Group 1 included 31 hypothyroid women with elevated thyroid stimulating hormone (TSH) (> 10 mU/L, > 10 µIU/mL) during pregnancy, and Group 2 had 21 euthyroid women with normal TSH levels (0.5-2.5 mU/L, 0.5-2.5 µIU/mL). Children underwent neuropsycological assessments using the Griffiths-II scale.

RESULTS

Pregnancy outcome showed an average gestational age at delivery of 38.2 weeks for hypothyroid women, compared to 40 weeks for controls, and average birth weight of 2855.6 g versus 3285 g for controls, with hypothyroid women having children with higher intrauterine growth restriction (IUGR) prevalence and more caesarean sections. The 1-min APGAR score was lower for the hypothyroid group's children, at 8.85 versus 9.52. Neuropsychological outcomes showed children of hypothyroid mothers scored lower in neurocognitive development, particularly in the learning and language subscale (subscale C), with a notable correlation between higher maternal TSH levels and lower subscale scores.

CONCLUSION

Fetuses born to hypothyroid mothers appeared to be at higher risk of IUGR and reduced APGAR score at birth. Neurocognitive development seemed to affect language performance more than the developmental quotient. This alteration appeared to correlate with the severity of hypothyroidism and its duration.

The Spectrum of Thyroid Dysfunction During Pregnancy and Fetomaternal Outcome, A Study from the Premier Institute of Western India

Background

Thyroid dysfunction evaluation during pregnancy is important for the mother's health, obstetric outcomes, and the child's cognitive development. This study is conducted to know various thyroid disorders that can occur during antenatal and their impact on mother and fetus outcomes.

Materials and Methods

This observational research was conducted over two years at a tertiary center in Western Rajasthan, India. Seven hundred and seventy-two low-risk singleton pregnant patients who met the inclusive criteria were recruited. The estimation of T3, T4, and TSH was done along with a routine investigation in antenatal women. Antenatal having abnormal thyroid profiles were then analyzed for mother and fetus problems.

Results

The prevalence of thyroid dysfunction in antenatal women is 16.5%. Subclinical hypothyroidism (SCH) was seen in 12.5% of cases, overt hypothyroidism in 3.36%, and subclinical hyperthyroidism in only 0.51% of cases. Anti-TPO was positive in 46 (41.44%) women with hypothyroidism and 1 (25%) with hyperthyroidism. Compared to euthyroid women, women with overt hypothyroid (19.23% vs 3.1%, P = 0.002) and subclinical hypothyroid (9.27% vs 3.1%, P = 0.003) were found to be associated with a higher risk of hypertensive disease. Concerning fetal outcomes. There was a high risk for preterm (12.37% v/s 4.9%, P = 0.004) and fetal growth retardation (FGR) in patients with SCH (7.21% v/s 3.1%, P = 0.04).

Conclusion

Considering the significant influence of thyroid disorders on mother and fetus outcomes, the screening for thyroid during pregnancy should be considered universally, particularly in developing countries with high prevalent rates, such as India.

Maternal hypothyroidism and the risk of preeclampsia: a Danish national and regional study

BACKGROUND

Maternal hypothyroidism in pregnancy has been proposed to increase the risk of preeclampsia, but uncertainties persist regarding the underlying causal mechanisms. Thus, it remains unclear if an increased risk of preeclampsia in hypothyroid pregnant women is caused by the lack of thyroid hormones or by the autoimmunity per se.

METHODS

We conducted a retrospective study of two pregnancy cohorts in the Danish population. The nationwide cohort (n = 1,014,775) was register-based and included all singleton pregnancies in Denmark from 1999-2015. The regional cohort (n = 14,573) included the biochemical measurement of thyroid stimulating hormone (TSH), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (Tg-Ab) (ADVIA Centaur XPT, Siemens Healthineers) among pregnant women in The North Denmark Region from 2011-2015 who had a blood sample drawn in early pregnancy as part of routine prenatal screening for chromosomal anomalies. The associations between diagnosed and biochemically assessed hypothyroidism and a diagnosis of preeclampsia were evaluated using logistic regression (adjusted odds ratio (aOR) with 95% confidence interval (CI)) adjusting for potential confounders, such as maternal age, diabetes, and parity.

RESULTS

In the nationwide cohort, 2.2% of pregnant women with no history of hypothyroidism (reference group (ref.)) were diagnosed with preeclampsia, whereas the prevalence was 3.0% among pregnant women with hypothyroidism (aOR 1.3 (95% CI: 1.2-1.4)) and 4.2% among women with newly diagnosed hypothyroidism in the pregnancy (aOR 1.6 (95% CI: 1.3-2.0)). In the regional cohort, 2.3% of women with early pregnancy TSH < 2.5 mIU/L (ref.) were diagnosed with preeclampsia. Among women with TSH ≥ 6 mIU/L, the prevalence was 6.2% (aOR 2.4 (95% CI: 1.1-5.3)). Considering thyroid autoimmunity, preeclampsia was diagnosed in 2.2% of women positive for TPO-Ab (> 60 U/mL) or Tg-Ab (> 33 U/mL) in early pregnancy (aOR 0.86 (95% CI: 0.6-1.2)).

CONCLUSIONS

In two large cohorts of Danish pregnant women, maternal hypothyroidism was consistently associated with a higher risk of preeclampsia. Biochemical assessment of maternal thyroid function revealed that the severity of hypothyroidism was important. Furthermore, results did not support an association between thyroid autoimmunity per se and preeclampsia.

Association between inadequate weight gain according to the institute of medicine 2009 guidelines and pregnancy outcomes in women with thyroid disorders

PURPOSE

Gestational weight gain (GWG) is an important contributor to pregnancy outcomes in the general obstetric population and different subgroups. The corresponding information in women with thyroid conditions is limited. We aimed to evaluate the relationship between GWG according to institute of medicine (IOM) and pregnancy outcomes in women with thyroid disorders.

METHODS

We performed a retrospective analysis of 620 pregnant women either treated with levothyroxine (N = 545) or attended because of hyperthyroidism during pregnancy (N = 75).

RESULTS

The associations between GWG according to IOM and pregnancy outcomes were present both in women treated with thyroid hormone and women followed by hyperthyroidism, most of them related to the fetal outcomes. In women treated with levothyroxine, insufficient GWG was associated with gestational diabetes mellitus (GDM) (odds ratio (OR) 2.32, 95% confidence interval (CI) 1.18, 4.54), preterm birth (OR 2.31, 95% CI 1.22, 4.36), small-for-gestational age newborns (OR 2.38, 95% CI 1.09, 5.22) and respiratory distress (OR 6.89, 95% CI 1.46, 32.52). Excessive GWG was associated with cesarean delivery (OR 1.66, 95% CI 1.10, 2.51) and macrosomia (OR 2.75, 95% CI 1.38, 5.49). Large-for-gestational age newborns were associated with both insufficient GWG (OR 0.25, 95% CI 0.11, 0.58) and excessive GWG (OR 1.80, 95% CI 1.11, 2.92). In women followed by hyperthyroidism, excessive GWG was associated with large-for-gestational age newborns (OR 5.56, 95% CI 1.03, 29.96).

CONCLUSION

GWG according to IOM is associated with pregnancy outcomes both in women treated with thyroid hormone and women followed by hyperthyroidism.

Levothyroxine initiation and the risk of pregnancy loss among pregnant women with subclinical hypothyroidism: An observational study emulating a target trial

BACKGROUND

While the benefits of levothyroxine are well-established for overt hypothyroidism, they are unclear for subclinical hypothyroidism (SCH) among pregnant women.

OBJECTIVE

To estimate the effect of initiation of levothyroxine on pregnancy loss among women with SCH with an emulated target trial using observational data.

METHODS

We emulated a target trial using the United Kingdom's Clinical Practice Research Datalink to account for the staggered timing of diagnosis and treatment of SCH and the time of entry of women into prenatal care. We emulated multiple nested trials (at each gestational week) and used an intention-to-treat approach to define levothyroxine use (≥1 prescription in the 7 days prior to trial entry), with eligible users matched to non-users (1:4) on time of diagnosis, gestational week of the first eligible trial and high-dimensional propensity score. Pregnancy losses included spontaneous abortion and stillbirth. A pooled logistic regression model with bootstrap resampling was used to estimate the hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

Based on 159,177 eligible person-trials (5781 women), the matched cohort included 181 initiators and 640 non-initiators of levothyroxine, with 57 pregnancy losses occurring during follow-up. Overall, the mean age of women was 32.2 years (SD 5.4), 25% were obese, 8% had type 2 diabetes and about 50% were nulliparous. After matching, women who initiated levothyroxine versus not had higher thyroid-stimulating levels during pregnancy and were more likely to have a history of hypothyroidism. The cumulative incidence of pregnancy loss was lower in initiators versus non-initiators of levothyroxine. The adjusted HR for pregnancy loss was 0.87 (95% CI 0.22, 1.56).

CONCLUSIONS

Although our assessment of the effect of initiation of levothyroxine for SCH in pregnancy precludes any definitive conclusions due to wide confidence intervals, this study illustrates the feasibility of using the target trial emulation framework to examine the effectiveness of medication use in pregnancy.

Characterization of a human thyroid microtissue model for testing thyroid disrupting chemicals

Perturbation of thyroid hormone (T4) synthesis is known to cause numerous developmental, metabolic, and cognitive disorders in humans. Due to species differences in sensitivity to chemical exposures, there is a need for human-based in vitro approaches that recapitulate thyroid cellular architecture and T4 production when screening. To address these limitations, primary human thyrocytes, isolated from healthy adult donor tissues and cryopreserved at passage one (p'1) were characterized for cellular composition, 3D follicular architecture, and thyroglobulin (TG)/T4 expression and inhibition by prototype thyroid disrupting chemicals (TDC). Flow analysis of the post-thaw cell suspension showed >80% EpCAM-positive cells with 10%-50% CD90-positive cells. When seeded onto 96-well Matrigel®-coated plates and treated with bovine thyroid stimulating hormone (TSH), thyrocytes formed 3D microtissues during the initial 4-5 days of culture. The microtissues exhibited a stable morphology and size over a 14-day culture period. TG and T4 production were highest in microtissues when the proportion of CD90-positive cells, seeding density and thyroid stimulating hormone concentrations were between 10%-30%, 6K-12K cells per well, and 0.03-1 mIU/mL, respectively. At maximal TG and T4 production levels, average microtissue diameters ranged between 50 and 200 µm. The T4 IC50 values for two prototype TPO inhibitors, 6-propyl-2-thiouracil and methimazole, were ∼0.7 µM and ∼0.5 µM, respectively, in microtissue cultures treated between days 9 and 14. Overall, p'1 cryopreserved primary human thyrocytes in 3D microtissue culture represent a promising new model system to prioritize potential TDC acting directly on the thyroid as part of a weight-of-evidence hazard characterization.

Quantitative proteomics reveals pregnancy prognosis signature of polycystic ovary syndrome women based on machine learning

OBJECTIVE

We aimed to screen and construct a predictive model for pregnancy loss in polycystic ovary syndrome (PCOS) patients through machine learning methods.

METHODS

We obtained the endometrial samples from 33 PCOS patients and 7 healthy controls at the Reproductive Center of the Second Hospital of Lanzhou University from September 2019 to September 2020. Liquid chromatography tandem mass spectrometry (LCMS/MS) was conducted to identify the differentially expressed proteins (DEPs) of the two groups. Gene Ontology (GO) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed to analyze the related pathways and functions of the DEPs. Then, we used machine learning methods to screen the feature proteins. Multivariate Cox regression analysis was also conducted to establish the prognostic models. The performance of the prognostic model was then evaluated by the receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA). In addition, the Bootstrap method was conducted to verify the generalization ability of the model. Finally, linear correlation analysis was performed to figure out the correlation between the feature proteins and clinical data.

RESULTS

Four hundred and fifty DEPs in PCOS and controls were screened out, and we obtained some pathways and functions. A prognostic model for the pregnancy loss of PCOS was established, which has good discrimination and generalization ability based on two feature proteins (TIA1, COL5A1). Strong correlation between clinical data and proteins were identified to predict the reproductive outcome in PCOS.

CONCLUSION

The model based on the TIA1 and COL5A1 protein could effectively predict the occurrence of pregnancy loss in PCOS patients and provide a good theoretical foundation for subsequent research.

The risk of developing gestational diabetes mellitus in maternal subclinical hypothyroidism: a systematic review and meta-analysis

PURPOSE

The purpose of this study was to determine the association between maternal subclinical hypothyroidism (SCH) and gestational diabetes mellitus (GDM) risk.

METHODS

This study is a systematic review and meta-analysis. Following PubMed, Medline, Scopus, Web of Science, and Google Scholar database search up to April 1 2021, a total of 4597 studies were identified. Studies published in English, with full text available, related to subclinical hypothyroidism in pregnancy, reporting or mentioning the incidence of GDM were included in the analysis. Following exclusion of studies, a total of 16 clinical trial were analyzed. For the risk of GDM, odds ratios (ORs) were calculated. Subgroup analyzes were performed according to gestational age and thyroid antibodies.

RESULTS

Pregnant women with SCH were at increased risk of GDM compared to women with euthyroidism, overall (OR = 1.339, 95% CI 1.041-1.724; p = 0.023). Additionally, SCH without thyroid antibodies has no significant effect on GDM risk (OR = 1.173, 95% CI 0.88-1.56; p = 0.277) and pregnant women with SCH in the first trimester were not found to be at increased risk of GDM compared to women with euthyroidism regardless of thyroid antibodies (OR = 1.088, 95%CI 0.816-1.451; p = 0.564).

CONCLUSIONS

Maternal SCH in pregnancy is related to an increased risk of GDM.

Associations between hypothyroidism and adverse obstetric and neonatal outcomes: a study of a population database including over 184,000 women with hypothyroidism

BACKGROUND

Maternal hypothyroidism has been associated with multiple adverse pregnancy outcomes. These findings have not been confirmed in a large population database study. Therefore, a large population-based cohort study was established to study the associations between maternal hypothyroidism and pregnancy and perinatal complications.

METHODS

This is a retrospective population-based cohort study utilizing data from the Healthcare Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) over 11 years from 2004 to 2014. A cohort of all deliveries between 2004 and 2014 inclusive, was created. Within this group, all deliveries to women with hypothyroidism were identified as part of the study group (n = 184,869), and the remaining deliveries were categorized as non-hypothyroidism births and comprised the reference group (n = 8,911,919). The main outcome measures were pregnancy and perinatal complications.

RESULTS

Maternal hypothyroidism is associated with several pregnancy and perinatal complications, including gestational diabetes mellitus (aOR 1.43, 95%CI 1.38-1.47), gestational hypertension (aOR 1.17, 95%CI 1.11-1.22) and preeclampsia (aOR 1.21, 95%CI 1.16-1.27) (all p < 0.001). These patients are more likely to experience preterm premature rupture of membranes (aOR 1.19, 95%CI 1.09-1.29, p < 0.001), preterm delivery (aOR 1.12 95%CI 1.08-1.17, p < 0.001), are more likely to deliver by cesarean section (aOR 1.21, 95% CI 1.18-1.24, p < 0.001), and suffer from postpartum hemorrhage (aOR 1.07, 95%CI 1.01-1.13, p = 0.012), disseminated intravascular coagulation (aOR 1.20, 95%CI 1.00-1.43, p = 0.046), and undergo hysterectomy (aOR 1.42, 95% CI 1.13-1.80, p = 0.003).As for neonatal outcomes, small for gestational age and congenital anomalies are more likely to occur in the offspring of women with hypothyroidism (aOR 1.20, 95% CI 1.14-1.27 and aOR 1.34, 95% CI 1.22-1.48, both p < 0.001).

CONCLUSIONS

Women with hypothyroidism are more likely to experience pregnancy, delivery and neonatal complications. We found an association between hypothyroidism and hypertensive disorders, postpartum hemorrhage, transfusions, infections, preterm delivery and hysterectomy, among other problems. This data from a population sized database confirms the findings of smaller previous studies in the literature.

Longitudinal trajectories of maternal TSH in healthy pregnant women in Catalonia

Objective

Longitudinal evaluation of thyroid function throughout pregnancy in the same subject could offer precise information about its dynamics as a physiological mechanism of adaption to the requirements. In this study, we evaluated longitudinal trajectories of maternal thyroid function during pregnancy by a latent class growth analysis and explored their association with maternal-fetal outcomes.

Methods

A prospective observational study was carried out, including 414 healthy pregnant women, from the first trimester to delivery. Thyroid function and autoimmunity were measured in the three trimesters. Clinical data during pregnancy were obtained. Longitudinal mixed model techniques were performed to explore trajectories of gestational thyroid function.

Results

Three different longitudinal trajectories were obtained from maternal thyrotropin (TSH) levels: low-increasing TSH (class 1) in 86% of cases, high-increasing TSH (class 2) in 9.7%, and decreasing TSH (class 3) in 4.3%. No statistical differences in free thyroxine levels were found among the three classes. Differences in maternal age (P = 0.027) and initial maternal weight (P = 0.043) were observed among the groups. In logistic regression analysis, maternal age correlated with longitudinal trajectories. The three longitudinal classes remain when women with thyroid autoimmunity (TAI) are excluded. Multinomial logistic regression showed maternal age correlated with longitudinal trajectories independently of TAI status.

Conclusions

Three differentiated TSH trajectories were found in healthy pregnant women living in Catalonia, as previously described. No association with obstetric outcomes was observed in these different chronological thyroid pathways, but maternal age might condition the longitudinal mechanism of thyroid function regulation throughout pregnancy.

Maternal hypothyroidism and its effect on placental histopathology in singleton live births resulting from in vitro fertilization treatment

We aimed to examine the impact of maternal hypothyroidism on placental pathology and perinatal outcomes in singleton live births resulting from IVF, using medical records of IVF births between 2009 and 2017 at a tertiary hospital. The primary outcomes included anatomical, inflammation, vascular malperfusion, and villous maturation placental features. Secondary outcomes included foetal, maternal, perinatal, and delivery complications. There were 1,057 live births, of which 103 (9.7%) and 954 (90.3%) were in the study and control groups, respectively. Patients in the study group were more likely to have diabetes mellitus, polycystic ovarian syndrome, gestational diabetes mellitus, and non-reassuring foetal heart rate (NRFHR) tracing during delivery. After adjustment for potential confounding factors, hypothyroidism was significantly associated with the bilobed placenta (aOR 4.1; 95% CI 1.2-14.3), retroplacental haematoma (aOR 2.4; 95% CI 1.2-4.9), decidual arteriopathy (aOR 2.0; 95% CI 1.2-4.1) and subchorionic thrombi (aOR 2.4; 95% CI 1.3-5.0). Additionally, there was a statistically significant relationship with NRFHR tracing. The incidence of acute chorioamnionitis and severe foetal inflammatory response was higher in the study group. In conclusion, the placental histopathology patterns of singleton IVF live births show that maternal hypothyroidism has a significant impact on adverse perinatal outcomes.

Prevalence, trends, and characteristics of polypharmacy among US pregnant women aged 15 to 44 years: NHANES 1999 to 2016

Polypharmacy has become a major health issue for pregnant woman due to the increased trend of medication use during pregnancy. However, data on medication use in pregnancy are limited since pregnant women are rarely included in clinical trials. Our study aimed to investigate the trends of and characteristics associated with polypharmacy among pregnant women in the US. This study was conducted using data from The National Health and Nutrition Examination Survey in the US. Nine The National Health and Nutrition Examination Survey cycles between 1999 and 2016 were used to identify pregnant women aged 15 to 44 years. Polypharmacy was defined as more than 1 medication prescription used during pregnancy. Descriptive statistics were used to report the prevalence and trends of polypharmacy. Multivariable logistic regression models were used to evaluate characteristics associated with polypharmacy among US pregnant women. Among 3,350,983 US pregnant women, about 7.4% of them (247,525) experienced polypharmacy. The prevalence of polypharmacy increased from 2.8% (1999-2000) to 10.0% (2015-2016) (P < .01) over-the time period examined in this study. Pregnant women were less likely to have experienced polypharmacy than were nonpregnant women (7.4% vs 23.5%, P < .01). Levothyroxine and albuterol were 2 prescriptions commonly taken by pregnant women. Pregnant women who were non-Hispanic white (P < .05) or had asthma (P < .05) or diabetes (P < .01) were more likely to report polypharmacy. Regarding personal characteristics, women with a poor or fair self-reported general health condition (odds ratio: 5.12, 95% confidence interval: 1.23-21.34) and those with chronic conditions (odds ratio: 6.91, 95% confidence interval: 3.08-15.50) were found to be associated with polypharmacy. An increased trend of polypharmacy was found in the US from 1999 to 2016. Non-Hispanic white pregnant women with a poor health status and chronic diseases were at an increased risk of polypharmacy.

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).

The association between hypothyroidism and perinatal outcomes in patients with polycystic ovary syndrome

PURPOSE

To compare pregnancy, delivery, and neonatal outcomes in patients with polycystic ovary syndrome (PCOS) with and without concomitant hypothyroidism.

METHODS

A retrospective population-based cohort study including all women with an ICD-9 diagnosis of PCOS in the US between 2004 and 2014, who delivered in the third trimester or had a maternal death. We compared women with a concomitant diagnosis of hypothyroidism to those without. Women with hyperthyroidism were excluded. Pregnancy, delivery, and neonatal outcomes were compared between the two groups.

RESULTS

Overall, 14,882 women met inclusion criteria. Among them, 1882 (12.65%) had a concomitant diagnosis of hypothyroidism, and 13,000 (87.35%) did not. Women with concomitant hypothyroidism, compared to those without, were characterized by increased maternal age (25.5% ≥ 35 years vs. 18%, p < 0.001, respectively), and had a higher rate of multiple gestations (7.1% vs. 5.7%, p = 0.023). Interestingly, pregnancy, delivery and neonatal outcomes were comparable between the groups, except for a higher rate of small-for-gestational-age (SGA) neonates in the group with hypothyroidism (4.1% vs. 3.2%, p = 0.033) (Tables 2 and 3). In a multivariate logistic regression adjusting for potential confounders, hypothyroidism was no longer found to be associated with SGA (adjusted odds ratio [aOR] 1.32, 95% confidence interval [CI] 0.99-1.75, p = 0.057), but was found to increase the odds for preeclampsia (aOR 1.30, 95% CI 1.06-1.59, p = 0.012).

CONCLUSIONS

In patients with PCOS, concomitant hypothyroidism significantly increases the risk for preeclampsia. Unexpectedly, other pregnancy complications commonly increased by hypothyroidism were not increased in women with PCOS, likely due to the inherent elevated baseline pregnancy risks of PCOS.

Maternal hyperthyroidism alters the immunological mediators profile and population of natural killers cells in decidua of rats

Decidual immunological mediators modulate placental formation, decidualization and fetal development. However, the effect of maternal hyperthyroidism on decidual immunology needs further research. The aim of this study was to evaluate the population of uterine natural killer cells (uNKs) and the expression of immunological mediators in the decidua of female rats throughout pregnancy. Wistar rats were used and hyperthyroidism was induced by daily administration of L-thyroxine (T4) throughout pregnancy. The population of uNK cells in decidua was evaluated by immunostaining Lectin DBA, as well as the expression of interferon γ (INFγ), macrophage migration inhibitory factor (MIF), interleukin 15 (IL-15) and inducible nitric oxide synthase (iNOS) at 7, 10, 12, 14 and 19 days of gestation (DG). Maternal hyperthyroidism reduced the DBA+ uNK cell population in the decidua at 7 (P < 0.05) and 10 (P < 0.01) DGs compared to that in the control group, while it increased in the basal decidua (P < 0.05) and metrial gland (P < 0.0001) at the 12th DG. Hyperthyroidism also increased immunostaining of IL-15 (P < 0.0001), INFγ (P < 0.05), and MIF (P < 0.05) in the 7th DG, and increased immunostaining of IL-15 (P < 0.0001) and MIF (P < 0.01) in ^the 10th DG. However, excess thyroxine reduced IL-15 expression in the metrial gland and/or basal decidua in the 12th (P < 0.05), 14th (P < 0.01), and 19th (P < 0.001) DGs, as was also observed for INFγ in the basal decidua (P<0.001) and metrial gland (P < 0.0001) in the 12th DG. Regarding iNOS, an antiinflammatory cytokine, lower expression was observed in the basal decidua of hyperthyroid animals at 7 and 12 DGs (P < 0.05), whereas an increase occurred in the 10th DG (P < 0.05). These data demonstrate that maternal hyperthyroidism in female rats, particularly between 7 and 10 DGs, reduces the population of DBA+ uNKs in the decidua and increases the expression of inflammatory cytokines, suggesting a more proinflammatory environment in early pregnancy caused by this gestational disease.

Incidence of and Risk Factors for Neonatal Hypothyroidism Among Women with Graves' Disease Treated with Antithyroid Drugs Until Delivery

Background: The incidence of neonatal hypothyroidism among newborns born to mothers with Graves' disease (GD) who continued antithyroid drug (ATD) treatment until delivery has never been reported. Objective: Our primary objective was to investigate the incidence of neonatal hypothyroidism among newborns born to mothers with GD who were treated with ATD until delivery. Our secondary objective was to identify the cutoff ATD daily doses for neonatal hypothyroidism risk, based on maternal thyrotropin (TSH) receptor antibody (TRAb) levels. Methods: We conducted a retrospective cohort study. We included 305 pregnant women with GD who were treated with an ATD until delivery (63 treated with methimazole [MMI] and 242 treated with propylthiouracil [PTU]). Umbilical cord TSH, free thyroxine (fT4), and TRAb levels were measured at delivery, and we investigated the respective relationships between neonatal hypothyroidism at delivery and maternal fT4 levels, TRAb levels, and daily ATD doses during pregnancy. Neonatal hypothyroidism was diagnosed when the umbilical cord fT4 level was below the lower limit of the reference range. Results: The incidence of neonatal hypothyroidism at delivery was 19.0% ([confidence interval, CI, 11.2-30.4]; 12/63) in the MMI group and 12.8% ([CI, 9.2-17.6]; 31/242) in the PTU group. Neonatal goiter was observed in one neonate in the PTU group, and two infants in the PTU group required levothyroxine treatment. The daily ATD dose in the third trimester was the strongest predictor of neonatal hypothyroidism at delivery; the cutoff MMI dose was 10 mg/day, and the cutoff PTU dose was 150 mg/day. When the maternal TRAb level in the third trimester was above three times the upper limit of the normal range, the cutoff MMI dose was 20 mg/day, and the cutoff PTU dose was 150 mg/day. Conclusions: Maternal fT4 and TRAb levels were higher in the neonatal hypothyroid group, which suggested prolonged GD activity. Careful follow-up is necessary when maternal GD remains active and the ATD dose to control maternal thyrotoxicosis cannot be reduced.

The impact of covid-19 on thyroid function tests in pregnancy

PURPOSE

To investigate the effects of laboratory-confirmed SARS-CoV-2 infection on thyroid function tests (TFTs) in pregnant women and to evaluate whether TFT changes are related to the severity and prognosis.

METHODS

Consecutive pregnant women tested for SARS-CoV-2 by RT-PCR at Ankara City Hospital were recruited between January 2021 and September 2021. Thyroid-stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3), thyroid peroxidase antibody (anti-TPO), and thyroglobulin antibody (anti-TG) were measured on admission.

RESULTS

Among 747 eligible pregnant women with the same baseline characteristics, 369 RT-PCR-positive women in the patient group and 378 RT-PCR-negative women in the control group were included in the analyses. Pregnant women in the patient group had significantly lower TSH, FT4, FT3, Anti TPO, and Anti TG concentrations compared with those in the control group (p < 0.001). The proportion of patient groups with mild, moderate, severe, and critical diseases were 297 (80.4%), 40 (10.8%), 17 (4.6%), and 15 (4.2%), respectively, among which with the moderate, severe, and critical disease had significantly lower FT3 values (2.5 vs 2.19 pg/mL, p < 0.001) and higher nonthyroidal illness syndrome (NTIS) (29.2 vs. 8.4%, p < 0.001) than those with mild disease. Lower FT3 values increased the risk of ICU admission, NICU admission, and severe disease (p < 0.001). FT3 and TSH correlated positively with lymphocytes (p < 0.001) and negatively correlated with C-reactive protein (CRP) (p < 0.001, p = 0.005).

CONCLUSION

The SARS-CoV-2 infection seems to have an impact on the TFTs of pregnant women, and particularly FT3 level seems to be correlated with disease severity.

Maternal Health, Pregnancy and Offspring Factors, and Maternal Thyroid Cancer Risk: A Nordic Population-Based Registry Study

Thyroid cancer incidence is higher in women than men, especially during the reproductive years, for reasons that remain poorly understood. Using population-based registry data from 4 Nordic countries through 2015, we examined associations of perinatal characteristics with risk of maternal thyroid cancer. Cases were women diagnosed with thyroid cancer ≥2 years after last birth (n = 7,425, 83% papillary). Cases were matched to controls (n = 67,903) by mother's birth year, country, and county of residence. Odds ratios (ORs) were estimated using conditional logistic regression models adjusting for parity. Older age at first pregnancy, postpartum hemorrhage (OR = 1.18, 95% (confidence interval) CI: 1.08, 1.29), and benign thyroid conditions (ORs ranging from 1.64 for hypothyroidism to 10.35 for thyroid neoplasms) were associated with increased thyroid cancer risk, as were higher offspring birth weight (per 1-kg increase, OR = 1.17, 95% CI: 1.12, 1.22) and higher likelihood of offspring being large for gestational age (OR = 1.26, 95% CI: 1.11, 1.43). Unmarried/noncohabiting status (OR = 0.91, 95% CI: 0.84, 0.98), maternal smoking (OR = 0.75, 95% CI: 0.67, 0.84), and preterm birth (OR = 0.90, 95% CI: 0.83, 0.98) were associated with reduced risk. Several factors (e.g., older age at first pregnancy, maternal smoking, goiter, benign neoplasms, postpartum hemorrhage, hyperemesis gravidarum, and neonatal jaundice) were associated with advanced thyroid cancer. These findings suggest that some perinatal exposures may influence maternal thyroid cancer risk.

Evaluating the Progression to Hypothyroidism in Preconception Euthyroid Thyroid Peroxidase Antibody-Positive Women

CONTEXT

Thyroid peroxidase antibody (TPOAb) positivity is prevalent in women of reproductive age and predisposes to thyroid dysfunction, particularly hypothyroidism, which has adverse effects on pregnancy.

OBJECTIVE

This study aimed to report the rate of development of abnormal thyroid function among initially euthyroid TPOAb-positive women recruited into the TABLET trial, to identify factors associated with the development of hypothyroidism, and to compare outcomes between euthyroid and treated hypothyroid individuals.

METHODS

This observational cohort study, conducted at 49 UK hospitals between 2011 and 2016, included euthyroid TPOAb-positive women 16 to 40 years of age with a history of miscarriage or subfertility, planning pregnancy, randomized to levothyroxine 50 mcg daily or placebo. Abnormal thyroid function, conception rate, and live birth rate (LBR) ≥34 weeks were analyzed.

RESULTS

Among the women, 70/940 (7.4%) developed subclinical (SCH) or overt (OH) hypothyroidism: 27/470 taking levothyroxine and 43/470 placebo (relative risk [RR] 0.63; 95% CI, 0.39-1.00; P = 0.05); 83% of cases emerged prepregnancy. Baseline median serum TSH concentrations and TPOAb titers were significantly higher in those who developed hypothyroidism vs those who did not (P < 0.001). Treated SCH/OH demonstrated a higher failure-to-conceive rate compared with euthyroid women (adjusted RR 2.02 [1.56-2.62]; P < 0.001). The LBR ≥ 34 weeks was similar in the treated SCH/OH and euthyroid groups (adjusted RR 1.09 [0.77-1.55]; P = 0.6).

CONCLUSION

Approximately 7% of euthyroid TPOAb-positive women will develop hypothyroidism within 1 year preconception or in pregnancy. Conception rates are lower in women with treated SCH/OH compared with euthyroid women, but LBR are comparable. Thyroid function in TPOAb-positive women should be monitored regularly, when trying to conceive, to ensure prompt diagnosis and appropriate treatment initiation.

Thyroid dysfunction in pregnancy - a retrospective observational analysis of a Maltese cohort

BACKGROUND

Thyroid dysfunction is known to adversely affect pregnancy. This study evaluates the prevalence of thyroid disorders and explores their association with pregnancy complications/comorbidities and modes of delivery in the Maltese pregnant population over a ten year period.

DESIGN

A population based observational study.

METHOD

We analysed data from the National Obstetrics Information Service of the Department of Health Informations and Research (NOIS) for all births delivered in Malta between 2006 and 2016. Cases identified and recorded by NOIS to have had some form of thyroid dysfunction during pregnancy were confirmed by cross-referencing  with laboratory results found in patients' medical records and/or iSOFT® database system. Using the Statistical Package for the Social sciences (SPSS®)  demographic data, past obstetric and medical history and obstetric outcomes were analysed for pregnancies with thyroid dysfunction and compared to data pertaining to pregnancies in euthyroid patients, that is those with no recorded thyroid dysfunction on NOIS. Chi square/Fisher's exact test were used to compare categorical variables while ANOVA/Mann-Whitney U test was used to compare continuous variables. Statistical significance was defined by a two-sided p value <0.05.

RESULTS

Data was available for 46,283 women (mean [SD] age = 29.2 [5.4] years). 587 pregnancies (1.3%) suffered from thyroid dysfunction. Of these, 67.3% were hypothyroid, 3.2% had hyperthyroidism, 28.3% had isolated hypothyroxinaemia (IHT) while 1.2% had a history of thyroid carcinoma. Patients with IHT and hypothyroidism were older than euthyroid patients (p < 0.001).  IHT and hypothyroid patients had a statistically significant higher body mass index (BMI) than euthyroid women (p=0.001 for hypothyroid women, p = 0.035 for IHT). Hypothyroid  and IHT women were more likely to have had a previous lower segment caesarean section  (p=0.043,  and 0.006 respectively). Type 1 diabetes and gestational diabetes  p = 0.012) were more common associated comorbidities in hypothyroid pregnancies. Offspring of patients with IHT had a higher birth weight than those born to euthyroid patients (p=0.009). Patients with hyperthyroidism were found to have a significantly increased risk of early preterm delivery before 34 weeks of gestation and were also more likely to have suspected intrauterine growth restriction and low mean birth weight. We report no significant differences in past history of obstetric loss, antenatal complications, mode of delivery, gestational age at delivery and postpartum haemorrhage rates across thyroid categories.

CONCLUSIONS

Available evidence suggests that thyroid dysfunction is more likely in the setting of older age, and higher body mass index. Moreover, it impacts on neonatal birth weight, rates of early preterm delivery and intrauterine growth restriction.

Maternal hypothyroidism and adverse outcomes of pregnancy

OBJECTIVE

Hypothyroidism has been associated with pregnancy complications, but uncertainty prevail regarding the severity and the role of thyroid autoimmunity. This study aimed to evaluate adverse pregnancy outcomes by exposure to maternal hypothyroidism and thyroid autoimmunity.

DESIGN

Retrospective cohort study.

PATIENTS

14,744 singleton pregnancies from the North Denmark Region Pregnancy Cohort (2011-2015).

MEASUREMENTS

Maternal thyroid stimulating hormone (TSH), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (Tg-Ab) were retrospectively measured in early pregnancy blood samples (ADVIA Centaur XPT, Siemens Healthineers). Adjusted odds ratio (aOR) with 95% confidence interval (CI) was used to estimate associations between maternal hypothyroidism (TSH cut-offs: 6.0 and 10 mIU/L), thyroid autoimmunity (TPO-Ab cut-off: 60 U/ml, Tg-Ab cut-off: 33 U/ml), and adverse pregnancy outcomes.

RESULTS

Pregnancy outcomes were 93.2% live births, 6.5% spontaneous abortions, and 0.3% stillbirths. The frequency of spontaneous abortion was 6.5% when TSH was below 6.0 mIU/L, 6.5% when above 6.0 mIU/L (aOR 1.0 [95% CI: 0.5-2.0]), and 12.5% when above 10 mIU/L (aOR: 2.0 [95% CI: 0.8-5.2]). For outcome of preterm birth, the frequency was 5.4% when TSH was below 6.0 mIU/L, 7.8% when above 6.0 mIU/L (aOR 1.5 [95% CI: 0.7-2.9]), and 11.4% when above 10 mIU/L (aOR: 2.6 [95% CI: 0.9-7.3]). No association was found between thyroid autoantibodies and spontaneous abortion (TPO-Ab: aOR: 1.0 [0.8-1.3], Tg-Ab: 1.0 [0.8-1.2]) or preterm birth (TPO-Ab: aOR: 1.0 [0.8-1.2], Tg-Ab: 0.9 [0.7-1.2]).

CONCLUSION

A high frequency of adverse pregnancy outcomes was seen among pregnancies exposed to maternal TSH above 10 mIU/L, whereas no association with thyroid autoantibodies was seen.

Delayed entry into prenatal care among women with pre-pregnancy health conditions, National Birth Defects Prevention Study, 1997-2011

First trimester entry into prenatal care is recommended for all women, and especially women with pre-pregnancy conditions. Our objective was to determine whether women with pre-pregnancy conditions were at lower risk of entry after the first trimester (delayed entry) into prenatal care than women without a pre-pregnancy health condition. We used data from 10,890 participants in the National Birth Defects Prevention Study who delivered liveborn infants without birth defects. Women reported pre-pregnancy conditions and timing of entry into prenatal care during a computer-assisted telephone interview. Multivariable logistic regression analyses were conducted to evaluate whether having a pre-pregnancy condition was associated with delayed entry into prenatal care compared to women without pre-pregnancy conditions. Approximately 13% of women reported delayed entry into prenatal care, and 18% of women reported a pre-pregnancy condition. Delayed entry into prenatal care was not associated with pre-pregnancy cardiometabolic or neurologic conditions. Women with thyroid conditions were less likely to report delayed entry into prenatal care (prevalence odds ratio (OR), 95% confidence interval (CI): 0.55 [0.32, 0.94]), but women with hematologic and respiratory conditions were more likely to report delayed entry into prenatal care (OR: 1.95 [1.00, 3.82] and 1.27 [0.95, 1.72], respectively), compared to those without any chronic conditions. Future research investigating the success of early prenatal care among women with thyroid conditions could identify ways to reduce delayed prenatal care among women with other pre-pregnancy conditions.

Evaluating thyroid function in pregnant women

Thyroid hormones are primarily responsible for regulating the basal metabolic rate but also make important contributions to reproductive function and fetal development. Both hyper- and hypothyroidism in pregnancy have been associated with increased risks of complications that include preeclampsia and low birth weight, among others. Furthermore, thyroid hormone deficiency in the developing fetus results in neurodevelopmental delay. As the fetus is exclusively reliant on maternal thyroid hormone for most of the first trimester and requires continued maternal supply until birth, identifying maternal thyroid dysfunction is critically important. However, evaluating thyroid function in pregnancy is challenging because of the many physiological changes that affect concentrations of thyroid-related analytes. Increasing plasma human chorionic gonadotropin (hCG) concentrations in the second half of the first trimester elicit a corresponding transient decrease in thyroid-stimulating hormone (TSH), and continually increasing estradiol concentrations throughout pregnancy cause substantial increases in thyroxine-binding globulin (TBG) and total thyroxine (T4) relative to the nonpregnant state. Lastly, free T4 concentrations gradually decrease with increasing gestational age. For these reasons, it is essential to interpret thyroid function test results in the context of trimester-specific reference intervals to avoid misclassification of thyroid status. This review summarizes the effects of thyroid dysfunction prior to conception and during pregnancy and describes considerations for the laboratory assessment of thyroid function in pregnant women.

Development and Validation of Risk Prediction Models for Gestational Diabetes Mellitus Using Four Different Methods

Gestational diabetes mellitus (GDM), a common perinatal disease, is related to increased risks of maternal and neonatal adverse perinatal outcomes. We aimed to establish GDM risk prediction models that can be widely used in the first trimester using four different methods, including a score-scaled model derived from a meta-analysis using 42 studies, a logistic regression model, and two machine learning models (decision tree and random forest algorithms). The score-scaled model (seven variables) was established via a meta-analysis and a stratified cohort of 1075 Chinese pregnant women from the Northwest Women's and Children's Hospital (NWCH) and showed an area under the curve (AUC) of 0.772. The logistic regression model (seven variables) was established and validated using the above cohort and showed AUCs of 0.799 and 0.834 for the training and validation sets, respectively. Another two models were established using the decision tree (DT) and random forest (RF) algorithms and showed corresponding AUCs of 0.825 and 0.823 for the training set, and 0.816 and 0.827 for the validation set. The validation of the developed models suggested good performance in a cohort derived from another period. The score-scaled GDM prediction model, the logistic regression GDM prediction model, and the two machine learning GDM prediction models could be employed to identify pregnant women with a high risk of GDM using common clinical indicators, and interventions can be sought promptly.

Urinary tetracycline antibiotics exposure during pregnancy and maternal thyroid hormone parameters: A repeated measures study

BACKGROUND

Studies on potential maternal thyrotoxicity related to tetracycline antibiotics exposure during pregnancy are lacking. Based on a large prospective cohort study, this study aimed to examine the associations between tetracycline antibiotics exposure in maternal urine and maternal thyroid hormone parameters.

METHODS

Based on the Ma'anshan Birth Cohort study, urine and serum samples of 2969 pregnant women were collected in the first, second and third trimesters. Tetracycline antibiotics, including oxytetracycline, chlorotetracycline, tetracycline and doxycycline in urine samples, as well as free thyroxine (FT4), thyroid stimulating hormone (TSH), total triiodothyronine (TT3) and total thyroxine (TT4) levels in serum samples, were measured. Linear mixed models and multivariate linear regression models were employed to examine associations between tetracycline antibiotics exposure during pregnancy and maternal thyroid hormone parameters.

RESULTS

The detection rates of four individual tetracycline antibiotics and all antibiotics (sum of four individual tetracycline antibiotics) in the three trimesters were 5.0%-52.3%, and the 95th percentile concentration ranged from 0.11 to 4.84 ng/mL. After adjusting for potential confounding factors, the repeated measures analyses indicated that pregnant women exposed to doxycycline and all antibiotics during the entire pregnancy were negatively associated with serum FT4 and TT4 levels but positively associated with serum TSH and TT3 levels. Trimester-stratified analyses found that doxycycline and all antibiotics exposure during the first trimester were negatively associated with serum FT4 and TT4 levels, while doxycycline was positively associated with TSH levels. In the third trimester, a significant association was only found between all antibiotics and TSH levels.

CONCLUSIONS

Our results suggest that exposure of pregnant women to tetracycline antibiotics is associated with maternal thyroid hormone parameters, and the first trimester might be the most critical window. More studies are needed to substantiate our findings and determine the underlying biological mechanisms.

Endocrine Emergencies During Pregnancy: Diabetic Ketoacidosis and Thyroid Storm

The physiologic changes and common signs and symptoms of pregnancy can make the early recognition of endocrine emergencies more challenging. Diabetic ketoacidosis (DKA) can occur at only modestly elevated glucose levels (euglycemic DKA), often accompanied by starvation ketosis due to substantial fetal-placental glucose demands and is associated with a high stillbirth rate. Thyroid storm is life threatening with a higher rate of heart failure and both require prompt and aggressive treatment to avoid maternal and fetal morbidity and mortality. Treatment of these disorders and the special considerations for recognition and management in the context of pregnancy are reviewed.

Effect of vitamin A on the relationship between maternal thyroid hormones in early pregnancy and fetal growth: A prospective cohort study

Background

Fetal growth patterns are influenced by maternal thyroid function and vitamin A level during pregnancy. Vitamin A presents interactions with thyroid tissues and hormonal systems. We examined whether vitamin A status modified the associations of maternal thyroid hormones in early pregnancy and fetal growth outcomes among euthyroid pregnant women in a prospective cohort study (n = 637).

Methods

We performed multiple linear regression and multinomial logistic regression analysis to investigate the effects of thyroid hormones in early pregnancy on fetal growth according to different levels of serum vitamin A based on median value.

Results

A 1 pmol/L increase in maternal free triiodothyronine (FT3) levels was associated with an increased birth weight of 0.080 kg (p = 0.023) in women with lower maternal vitamin A levels in early pregnancy. Increased maternal free thyroxine (FT4) was associated with decreased odds for both small size for gestational age (SGA) [odds ratios (OR) = 0.66, 95% confidence interval (CI): 0.45–0.95] and large size for gestational age (LGA) (OR = 0.66, 95% CI: 0.45–0.98) in women with higher vitamin A level in early pregnancy after adjustment for maternal prepregnancy body mass index, gestational weight gain, maternal employed, parity, gestational week at sampling, and gestational diabetes mellitus.

Conclusions

In Chinese pregnant women without overt thyroid dysfunction, maternal FT4 in early pregnancy was positively associated with optimal fetal growth among women with higher serum vitamin A concentrations.

Association of Preconception Thyrotropin Levels With Fecundability and Risk of Spontaneous Abortion in China

IMPORTANCE

Abundant evidence suggests thyroid dysfunction is associated with adverse pregnancy outcomes. However, associations of preconception thyrotropin levels outside of reference range with reproductive health outcomes are not well characterized.

OBJECTIVE

To evaluate the associations of preconception thyrotropin levels with time to pregnancy (TTP) and risk of spontaneous abortion (SA).

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used data from the Chinese National Free Prepregnancy Checkups Project. Female participants aged 20 to 49 years who were trying to conceive were enrolled between January 1, 2013, and December 31, 2016, for the analysis of TTP or SA. Data were analyzed between August 1, 2020, and July 5, 2021.

EXPOSURES

Levels of thyrotropin within 1 year prior to pregnancy.

MAIN OUTCOMES AND MEASURES

The main outcomes were TTP, assessed using hazard ratios (HRs), and SA, assessed using odds ratios (ORs), according to preconception thyrotropin levels. Thyrotropin dose-response associations were assessed using restricted cubic spline regression.

RESULTS

Among 11 194 002 female participants (mean [SD] age, 27.56 [5.10] years) in the TTP cohort, 4 739 421 (42.34%) participants became pregnant within 1 year. Both low and high preconception thyrotropin levels were associated with delayed TTP compared with thyrotropin levels of 0.37 to 2.49 mIU/L (thyrotropin <0.10 mIU/L: HR, 0.90; 95% CI, 0.89-0.92; thyrotropin 4.88-9.99 mIU/L: HR, 0.86; 95% CI, 0.86-0.87; thyrotropin ≥10.00 mIU/L: HR, 0.78; 95% CI, 0.77-0.79). In the SA analysis cohort including 4 678 679 pregnancies, 108 064 SA events (2.31%) were documented. High thyrotropin groups showed an increased risk of SA compared with the group with thyrotropin levels of 0.37 to 2.49 mIU/L (thyrotropin 4.88-9.99 mIU/L: OR, 1.33; 95% CI, 1.28-1.38; thyrotropin ≥10.00 mIU/L: OR, 1.25; 95% CI, 1.14-1.36). Preconception thyrotropin levels showed an inverted J-shaped dose-response association with TTP (χ2 = 311.29; nonlinear P < .001) and a J-shaped dose-response association with SA (χ2 = 58.29; nonlinear P < .001).

CONCLUSIONS AND RELEVANCE

In this cohort study, preconception thyrotropin levels outside of reference range were associated with increased risk of reduced fecundity and SA. These findings may provide insights for the implementation of preconception thyroid function screening and the design of future levothyroxine supplementation trials.

Outcomes of Early-Pregnancy Antithyroid Drug Withdrawal in Graves' Disease: A Preliminary Prospective Follow-Up Study

Objective: The use of antithyroid drugs (ATDs) carries potential risk for teratogenic effects. For women with well-controlled hyperthyroidism on a low dose of ATDs, drug withdrawal upon pregnancy is recommended by international medical guidelines. Therefore, it is necessary to determine the characteristics of patients suitable for ATD withdrawal, subsequent changes in thyroid function after ATD discontinuation, and its impact on pregnancy and offspring outcomes. Methods: This prospective study recruited 63 pregnant women with well-controlled Graves' hyperthyroidism who had stopped ATDs during early pregnancy. Patients were followed up until the end of pregnancy and data on pregnancy outcomes were collected. Results: Overall, 20 patients (31.7%) had rebound of hyperthyroidism. Patients with either subnormal thyrotropin (TSH) levels (TSH <0.35 mIU/L, odds ratio [OR] = 5.12, confidence interval [CI = 1.29-20.34], p = 0.03) or positive thyrotropin receptor antibody (TRAb) (TRAb >1.75 IU/L, OR = 3.79, [CI = 1.17-12.30], p = 0.02) at the time of ATDs withdrawal presented a higher risk of rebound than those with either normal TSH levels or negative TRAb. Patients with both subnormal TSH and positive TRAb at the time of ATD withdrawal were more likely to experience rebound (83.3%, 5/6) than those with both normal TSH and negative TRAb (13%, 3/23, OR = 33.33, [CI = 2.83-392.60], p = 0.003). The prevalence of adverse pregnancy outcomes was significantly higher in patients who experienced rebound compared with those who did not (55.0% vs. 9.3%, OR = 11.92, [CI = 3.08-46.18], p = 0.0002). Conclusions: Subnormal TSH levels and TRAb positivity at the time of ATD withdrawal in early pregnancy may be associated with rebound of Graves' hyperthyroidism. Rebound of hyperthyroidism during pregnancy may increase the risk of adverse pregnancy outcomes. Larger prospective studies are needed to confirm these findings.

Levothyroxine treatment for subclinical hypothyroidism improves the rate of live births in pregnant women with recurrent pregnancy loss: a randomized clinical trial

Objective: This study aimed to assess whether the use of levothyroxine was beneficial in pregnant women with subclinical hypothyroidism (SCH) or women who were positive for thyroid peroxidase antibody (TPOAb⁺).Study design: This was a randomized clinical trial involving 1736 populations of pregnant women. Our study was conducted into two groups: normal pregnant group and recurrent pregnancy loss (RPL) pregnant group. Both patients were divided into SCH and TPOAb⁺ groups, respectively; the patients of four groups were randomized into either the L-T4 treatment or control groups.Results: There was no significant difference between the two groups in the prevalence of SCH and TPOAb⁺ (p > .05); The live births rate of normal pregnant group was higher than that of the RPL pregnant Group (79.5% vs. 70.8%, p < .05); Considering normal pregnant women, whether women who were TPOAb ⁺ or SCH, there was no significant difference between the treatment and control group in the live birth rate and the pregnancy loss rate. In RPL group, whether women who were TPOAb⁺ or SCH, L-T4 treatment can obtain higher live birth rate and lower abortion rate compared to the control.Conclusion: There was no significant difference between normal and RPL pregnant women in the prevalence of SCH and TPOAb⁺.Treatment with L-T4 decreased the risk of pregnancy loss and increased the live birth rate in RPL pregnant women who were positive for TPOAb or subclinical hypothyroidism. Levothyroxine therapy is recommended for SCH and TPOAb⁺ women in pregnant women with recurrent pregnancy loss.

Management of Hypothyroidism and Hypothyroxinemia in Pregnancy

OBJECTIVE

To review the diagnosis and management of hypothyroidism in pregnancy, preconception, and the postpartum period.

METHODS

Literature review of English-language papers published between 1982 and 2022, focusing on the most recent literature.

RESULTS

During pregnancy, thyroid function laboratory tests need to be interpreted with regard to gestational age. Overt hypothyroidism, regardless of the TSH level, should always be promptly treated when it is diagnosed preconception or during pregnancy or lactation. Most women with preexisting treated hypothyroidism will require an increase in levothyroxine dosing to maintain euthyroidism during gestation. levothyroxine-treated pregnant patients need close monitoring with serum thyroid stimulating hormone (TSH) to avoid or- or under treatment. There is no consensus about whether to initiate levothyroxine in women with mild forms of gestational thyroid hypofunction. However, in light of current evidence it is reasonable to treat subclinically hypothyroid women with levothyroxine, particularly if the TSH is >10 mIU/L or the thyroperoxidase antibody is positive. Women who are not treated need to be followed to ensure that treatment is initiated promptly if thyroid failure progresses. Additional studies are needed to better understand the effects of the initiation of levothyroxine in early gestation in subclinically hypothyroid and hypothyroxinemic women and to determine optimal strategies for thyroid function screening in preconception and pregnancy.

CONCLUSION

The diagnosis and management of hypothyroidism in the peripregnancy period present specific challenges. In making management decisions, it is essential to weigh the risks and benefits of treatments not just for the mother but also for the fetus.

Mediation by hormone concentrations on the associations between repeated measures of phthalate mixture exposure and timing of delivery

BACKGROUND

Phthalates are used in the manufacturing of consumer products, resulting in ubiquitous human exposure to phthalate mixtures. Previous work has suggested that phthalates display endocrine-disrupting capabilities, and exposure is associated with early delivery.

OBJECTIVE

To assess mediating effects of hormone concentrations on associations between phthalate mixtures and preterm birth (PTB).

METHODS

Repeated urinary phthalates and serum hormones were measured among 1011 women in the PROTECT Puerto Rico birth cohort from 2011-2019. We utilized ridge regression to create phthalate environmental risk scores (ERS), which represent weighted summaries of total phthalate exposure. Mediation analyses were conducted on a subset of 705 women. We additionally conducted fetal sex-specific analyses.

RESULTS

Free thyroxine (FT4) mediated 9.6% of the association between high molecular weight (HMW) ERS at 18 weeks and reduced gestational age at delivery (95%CI:1.07-29.9). Progesterone at 26 weeks mediated 21.1% and 16.2% of the association between HMW ERS at 18 and 22 weeks, and spontaneous PTB, respectively. Among male fetuses, corticotropin releasing hormone (CRH) at 18 weeks mediated 28.2% of the association between low molecular weight ERS and spontaneous PTB.

SIGNIFICANCE

We provide introductory evidence of hormone disruption on the causal pathway between phthalate exposure and early delivery. We also show differences by fetal sex, but larger sample size is necessary to validate our findings.

IMPACT STATEMENT

This study provides introductory evidence that an alteration of hormone concentrations occurs on the causal pathway between gestational phthalate mixture exposure and subsequent PTB. In addition to the novel application of repeated biomarker measurements and mixtures methods in causal mediation analyses, we also explored differences between classes of phthalate compounds and between fetal sexes. We show that differential endocrine pathways may be disrupted with exposures to low versus HMW phthalate compounds, and that pregnancies with a male fetus may be more susceptible to endocrine disruption than those with a female fetus.

Pregnancy Outcomes in Women with Thyroid Diseases

Introduction

Overt hyperthyroidism and hypothyroidism are associated with pregnancy complications; however, most women with these conditions are diagnosed before conception and are under treatment during pregnancy, especially in high-income countries. The purpose of this study was to investigate pregnancy complications among these women.

Methods

A retrospective cohort study was conducted, and data on pregnant women who gave birth to a singleton at Nagoya University Hospital in Japan in 2005-2014 was collected. The pregnancy outcomes were divided and compared among three groups: the control group (n = 3531), the hyperthyroidism group (n = 48), and the hypothyroidism group (n = 61). Additionally, risk factors for placental abruption were evaluated by multivariable logistic regression analysis. Moreover, in hyperthyroidism, thyroid function at the placentation period was compared between placental-related diseases and nonplacental-related disease groups, and the latter group included placental abruption and preeclampsia.

Results

The incidence of placental abruption was higher in hyperthyroidism than in control and hypothyroidism groups. Hyperthyroidism was independently associated with an increased risk of placental abruption (adjusted odds ratio, aOR = 8.21, 95% confidence interval, CI: 1.76-38.34), as well as preeclampsia (aOR = 4.10, 95% CI: 1.13-14.76) and preterm labor (aOR = 3.38, 95% CI: 1.19-9.64). Additionally, thyroid-stimulating hormone (TSH) at the placentation period was significantly lower in the placental-related disease group than in the nonplacental-related disease group (p < 0.05).

Conclusions

Pregnancy outcomes in women with hyperthyroidism and hypothyroidism would be comparable with those without thyroid disease. Hyperthyroidism was an independent risk factor for placental abruption as well as preterm labor and preeclampsia. However, its frequency was extremely low, and further research is required to validate our findings.

Thyroid Dysfunction among Hypertensive Pregnant Women in Warri, Delta State, Nigeria

The hypertensive pregnant woman is at a higher risk of complications either before, during or after birth and the baby can be adversely affected leading to preterm birth, low birth weight, placental separation (abruption) and other complications. The aim of the study was to evaluate thyroid dysfunction among pregnant women with hypertension. The study participants were 150 hypertensive pregnant women, 25 non-hypertensive pregnant women and 25 non-hypertensive non-pregnant women. Exactly 5mL of blood was collected and used for the assay of triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH) using the enzyme-linked immunosorbent assay technique. Data were analyzed using appropriate statistical tools. The results showed a significantly higher (p < 0.05) age among hypertensive pregnant women when compared with non-hypertensive pregnant women and non-hypertensive non-pregnant women. The serum TSH was significantly higher (p < 0.035) among hypertensive pregnant women when compared with non-hypertensive pregnant women. The triiodothyronine (T3) of hypertensive pregnant women was observed to be significantly higher (p < 0.05) when compared with both non-hypertensive pregnant women and non-hypertensive non-pregnant women. Some 15/150 (10%) of hypertensive pregnant women had subclinical hypothyroidism, 13/150 (8.7%) had overt hypothyroidism, while 122/150 (81.3%) were euthyroid. Among those with thyroid dysfunction, five and four of the subjects had subclinical hypothyroidism and overt hypothyroidism during the second trimester, while ten and nine had subclinical hypothyroidism and overt hypothyroidism during the third trimester, respectively. Evaluation of hypertensive pregnant women for thyroid function may be routinely performed to enable early diagnosis and treatment.

Association between maternal thyroid function and risk of gestational hypertension and pre-eclampsia: a systematic review and individual-participant data meta-analysis

BACKGROUND

Adequate maternal thyroid function is important for an uncomplicated pregnancy. Although multiple observational studies have evaluated the association between thyroid dysfunction and hypertensive disorders of pregnancy, the methods and definitions of abnormalities in thyroid function tests were heterogeneous, and the results were conflicting. We aimed to examine the association between abnormalities in thyroid function tests and risk of gestational hypertension and pre-eclampsia.

METHODS

In this systematic review and meta-analysis of individual-participant data, we searched MEDLINE (Ovid), Embase, Scopus, and the Cochrane Database of Systematic Reviews from date of inception to Dec 27, 2019, for prospective cohort studies with data on maternal concentrations of thyroid-stimulating hormone (TSH), free thyroxine (FT₄), thyroid peroxidase (TPO) antibodies, individually or in combination, as well as on gestational hypertension, pre-eclampsia, or both. We issued open invitations to study authors to participate in the Consortium on Thyroid and Pregnancy and to share the individual-participant data. We excluded participants who had pre-existing thyroid disease or multifetal pregnancy, or were taking medications that affect thyroid function. The primary outcomes were documented gestational hypertension and pre-eclampsia. Individual-participant data were analysed using logistic mixed-effects regression models adjusting for maternal age, BMI, smoking, parity, ethnicity, and gestational age at blood sampling. The study protocol was registered with PROSPERO, CRD42019128585.

FINDINGS

We identified 1539 published studies, of which 33 cohorts met the inclusion criteria and 19 cohorts were included after the authors agreed to participate. Our study population comprised 46 528 pregnant women, of whom 39 826 (85·6%) women had sufficient data (TSH and FT₄ concentrations and TPO antibody status) to be classified according to their thyroid function status. Of these women, 1275 (3·2%) had subclinical hypothyroidism, 933 (2·3%) had isolated hypothyroxinaemia, 619 (1·6%) had subclinical hyperthyroidism, and 337 (0·8%) had overt hyperthyroidism. Compared with euthyroidism, subclinical hypothyroidism was associated with a higher risk of pre-eclampsia (2·1% vs 3·6%; OR 1·53 [95% CI 1·09-2·15]). Subclinical hyperthyroidism, isolated hypothyroxinaemia, or TPO antibody positivity were not associated with gestational hypertension or pre-eclampsia. In continuous analyses, both a higher and a lower TSH concentration were associated with a higher risk of pre-eclampsia (p=0·0001). FT₄ concentrations were not associated with the outcomes measured.

INTERPRETATION

Compared with euthyroidism, subclinical hypothyroidism during pregnancy was associated with a higher risk of pre-eclampsia. There was a U-shaped association of TSH with pre-eclampsia. These results quantify the risks of gestational hypertension or pre-eclampsia in women with thyroid function test abnormalities, adding to the total body of evidence on the risk of adverse maternal and fetal outcomes of thyroid dysfunction during pregnancy. These findings have potential implications for defining the optimal treatment target in women treated with levothyroxine during pregnancy, which needs to be assessed in future interventional studies.

FUNDING

Arkansas Biosciences Institute and Netherlands Organization for Scientific Research.

Short-Term Adverse Pregnancy Outcomes in Women with Subclinical Hypothyroidism: A Comparative Approach of Iranian and American Guidelines

Introduction

Subclinical hypothyroidism during pregnancy can be associated with numerous adverse outcomes. The purpose of this study was to compare short-term adverse pregnancy outcomes in treated versus nontreated patients who fall within the numerical range of thyroid-stimulating hormone (TSH) between the Iranian and American reference ranges.

Materials and Methods

Eighty pregnant women with a known level of antithyroid peroxidase (anti-TPO) and TSH levels of 2.5–3.9 mIu/L in the first trimester and 3–4.1 mIu/L in the second and third trimesters were enrolled in the study and randomly assigned into two groups including 41 patients in the intervention group and 39 in the control group. The intervention group was treated with levothyroxine at least 50 μg/day and the control group received no treatment. The data were analyzed by SPSS software version 23.

Results

The only significant findings were a correlation between pregnancy loss frequency (p − 0.011) and/or increased TSH level in the follow-up period (p = 0.008) with anti-TPO antibody positivity. Forty-four percent of mothers with positive anti-TPO Ab needed treatment initiation with levothyroxine, based on Iranian guidelines, due to increased TSH level during the follow-up period.

Conclusion

Untreated pregnant women with subclinical hypothyroidism, who were placed in the intermediate range of TSH, recommended by Iranian and American guidelines, did not show any significant difference in short-term adverse pregnancy outcomes compared to the treated patients. Positive anti-TPO Ab may play a role in the development of short-term complications in mothers with subclinical hypothyroidism or it may increase the likelihood of an increase in TSH level during pregnancy.

Assessment and treatment of thyroid disorders in pregnancy and the postpartum period

Thyroid disorders are prevalent in pregnant women. Furthermore, thyroid hormone has a critical role in fetal development and thyroid dysfunction can adversely affect obstetric outcomes. Thus, the appropriate management of hyperthyroidism, most commonly caused by Graves disease, and hypothyroidism, which in iodine sufficient regions is most commonly caused by Hashimoto thyroiditis, in pregnancy is important for the health of both pregnant women and their offspring. Gestational transient thyrotoxicosis can also occur during pregnancy and should be differentiated from Graves disease. Effects of thyroid autoimmunity and subclinical hypothyroidism in pregnancy remain controversial. Iodine deficiency is the leading cause of hypothyroidism worldwide. Despite global efforts to eradicate iodine deficiency disorders, pregnant women remain at risk of iodine deficiency due to increased iodine requirements during gestation. The incidence of thyroid cancer is increasing worldwide, including in young adults. As such, the diagnosis of thyroid nodules or thyroid cancer during pregnancy is becoming more frequent. The evaluation and management of thyroid nodules and thyroid cancer in pregnancy pose a particular challenge. Postpartum thyroiditis can occur up to 1 year after delivery and must be differentiated from other forms of thyroid dysfunction, as treatment differs. This Review provides current evidence and recommendations for the evaluation and management of thyroid disorders in pregnancy and in the postpartum period.

Associations between thyroid function and gestational diabetes mellitus in Chinese pregnant women: a retrospective cohort study

BACKGROUND

Thyroid function is known to be closely linked with type 2 diabetes, but data on the association between thyroid function and gestational diabetes mellitus (GDM) are inconsistent.

METHODS

A total of 2849 pregnant women were included in this retrospective study. Serum concentrations of thyroid indicators (free tetraiodothyronine, FT4; thyroid-stimulating hormone, TSH; and thyroid peroxidase antibody, TPO Ab) were obtained from a clinical laboratory. The presence of GDM were drawn from medical records. The clinical subtypes of thyroid function (euthyroidism, subclinical hypothyroidism, hyperthyroidism, and isolated hypothyroxinemia) were categorized according to the thresholds of the 2.5^th/97.5^th and 10^th/90^th percentiles of TSH and FT4 concentrations. A concentration of > 34 IU/L was defined as indicating TPO Ab-positivity.

RESULTS

Two hundred and thirty-five (8.25%) of the 2849 women were TPO Ab-positive. Higher serum concentrations of FT4 (top vs. bottom tertiles) was found to be negatively associated with the risk of GDM. The corresponding odds (OR) values (top tertile vs. bottom tertile) were 0.71 [95% confidence interval (CI): 0.54, 0.93]. No significant associations were observed between the extremely 2.5^th/97.5^th or 10^th/90^th percentiles of FT4 concentration, TSH concentration, thyroid function subtypes (vs. euthyroidism), TPO Ab-positivity (vs. -negativity), and the GDM risk. The corresponding results remained similar when TPO Ab-positive subjects were excluded.

CONCLUSIONS

A negative association with the risk of GDM was observed for the highest FT4 concentrations tertile. No significant associations were found between the TSH concentration, thyroid function subtypes, TPO Ab positivity, and the GDM risk.

Maternal Hypothyroidism in Rats Reduces Placental Lactogen, Lowers Insulin Levels, and Causes Glucose Intolerance

Hypothyroidism increases the incidence of gestational diabetes mellitus (GDM) but the mechanisms responsible are unknown. This study aimed to assess the pathophysiological mechanisms by which hypothyroidism leads to glucose intolerance in pregnancy. 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 1 week before pregnancy and throughout gestation. A nonpregnant cohort received the same dose for the same duration but were not mated. On gestational day 16 (GD16), or nonpregnant day 16 (NP16), animals were subjected to an intraperitoneal glucose tolerance test. Tissues and blood samples were collected 4 days later. Hypothyroidism induced a diabetic-like phenotype by GD16 in pregnant females only. Pregnant MOD and SEV females had reduced fasting plasma insulin, less insulin following a glucose load, and altered expression of genes involved in insulin signaling within skeletal muscle and adipose tissue. Hypothyroidism reduced rat placental lactogen concentrations, which was accompanied by reduced percentage β-cell cross-sectional area (CSA) relative to total pancreas CSA, and a reduced number of large β-cell clusters in the SEV hypothyroid group. Plasma triglycerides and free fatty acids were reduced by hypothyroidism in pregnant rats, as was the expression of genes that regulate lipid homeostasis. Hypothyroidism in pregnant rats results in a diabetic-like phenotype that is likely mediated by impaired β-cell expansion in pregnancy. This pregnancy-specific phenomenon is likely due to reduced placental lactogen secretion.

Hypertension in Pregnancy: Diagnosis, Blood Pressure Goals, and Pharmacotherapy: A Scientific Statement From the American Heart Association

Hypertensive disorders of pregnancy (HDP) remain one of the major causes of pregnancy-related maternal and fetal morbidity and mortality worldwide. Affected women are also at increased risk for cardiovascular disease later in life, independently of traditional cardiovascular disease risks. Despite the immediate and long-term cardiovascular disease risks, recommendations for diagnosis and treatment of HDP in the United States have changed little, if at all, over past decades, unlike hypertension guidelines for the general population. The reasons for this approach include the question of benefit from normalization of blood pressure treatment for pregnant women, coupled with theoretical concerns for fetal well-being from a reduction in utero-placental perfusion and in utero exposure to antihypertensive medication. This report is based on a review of current literature and includes normal physiological changes in pregnancy that may affect clinical presentation of HDP; HDP epidemiology and the immediate and long-term sequelae of HDP; the pathophysiology of preeclampsia, an HDP commonly associated with proteinuria and increasingly recognized as a heterogeneous disease with different clinical phenotypes and likely distinct pathological mechanisms; a critical overview of current national and international HDP guidelines; emerging evidence that reducing blood pressure treatment goals in pregnancy may reduce maternal severe hypertension without increasing the risk of pregnancy loss, high-level neonatal care, or overall maternal complications; and the increasingly recognized morbidity associated with postpartum hypertension/preeclampsia. Finally, we discuss the future of research in the field and the pressing need to study socioeconomic and biological factors that may contribute to racial and ethnic maternal health care disparities.

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.