Meta-analysis of the association between maternal subclinical hypothyroidism and gestational diabetes mellitus

Pregnancy outcome in subclinical hypothyroidism with and without thyroid peroxidase antibodies-a prospective cohort study

BACKGROUND

Subclinical hypothyroidism (SCH) in pregnancy is associated with adverse foetomaternal outcomes. The literature is scarce with respect to maternal and perinatal outcomes in women with mild SCH (TSH levels between 2.5-4 mIU/L).

OBJECTIVES

The primary objective of the study was to compare the pregnancy outcome between SCH and euthyroid women. The secondary objectives were to find out the proportion of women with SCH having thyroid peroxidase antibodies (TPOAb) and to see the effect of TPOAb positivity on foetomaternal outcomes.

MATERIALS AND METHODS

A total of 178 pregnant women were recruited in the first trimester, and those with TSH between 0.1 and 2.4 mIU/L were considered as euthyroid and 2.5-4mIU/L were labelled as SCH. Women with SCH underwent testing for TPOAb. All women were followed until delivery, and foetomaternal outcomes were assessed.

RESULTS

Amongst SCH group, there was a significantly higher proportion of overweight and obese women (76/91 (83.51%) vs 59/87 (68%), p = 0.031). The neonatal intensive care unit (NICU) admission was higher with adjusted odds ratio of 3.24 (1.41-7.43) in women with SCH as compared to euthyroid women. Otherwise, there was no difference in foetomaternal outcomes between the two groups. The proportion of gestational diabetes mellitus, intrauterine growth retardation and still birth were higher in SCH women with TPOAb as compared to euthyroid. Amongst SCH women, the proportion of induced labour was lower (aOR:0.27 (0.08-0.93) whereas the proportion of stillbirth and low APGAR scores were higher in TPOAb-positive women with a statistically significant difference and adjusted odds ratio (aOR:20.18 (1.84-220.83)) and (aOR:4.77 (1.06-21.3)), respectively, when compared to TPOAb-negative women.

CONCLUSION

There appears to be no difference in pregnancy outcomes between women with SCH and euthyroid women except higher NICU admission in SCH group. Future multi-centre large prospective studies are required to understand better about the pregnancy outcomes in these women.

Comparison of Factors Influencing Gestational Outcomes in Healthy Versus Hypothyroid Women from Karachi, Pakistan

BACKGROUND

Gestational outcomes are known to be negatively correlated with hypothyroidism. This study was designed to compare the maternal factors affecting gestational outcomes in women with and without hypothyroidism.

METHODS

This retrospective analysis was carried out in a tertiary hospital in Karachi, Pakistan, between 2008 and 2016. A standardized form was used to collect information on the age of the mother, gestational duration at the prenatal appointment, gestational diabetes mellitus (GDM), hypertension, and past records of miscarriages in hypothyroid and healthy pregnant women. Gestational outcomes were recorded as live birth or pregnancy loss. Statistical analysis was performed to examine overt versus sub-clinical hypothyroidism and among those diagnosed before versus during gestation.

RESULTS

A collective of 708 women were enlisted in the hypothyroid pregnant group and 759 were recruited in healthy controls. Pregnancy loss was 9.9% (n=70) in hypothyroid women, whereas it was 14.3% (n=108) in the control group. The age of the mother, gestational duration at the prenatal appointment, and past records of miscarriages were discovered to be related to a higher chance of pregnancy loss in a multivariable analysis, but GDM (OR 0.04, CI 0.06-0.32, P=0.002) and hypothyroidism (OR 0.62, CI 0.43-0.89, P=0.01) exhibited a protective effect.

CONCLUSION

This study found the age of the mother, gestational duration at a prenatal appointment, and past records of miscarriages to be associated with negative outcomes in hypothyroidism. These factors remained significant in overt as well as subclinical hypothyroid women.

Autoimmune diseases and adverse pregnancy outcomes: an umbrella review

BACKGROUND

There is a high prevalence of autoimmune conditions in women specially in the reproductive years; thus, the association with adverse pregnancy outcomes has been widely studied. However, few autoimmune conditions/adverse outcomes have been studied more than others, and this umbrella review aims to consolidate existing knowledge in this area with the aim to provide new knowledge and also identify gaps in this research area.

METHODS

Medline, Embase, and Cochrane databases were searched from inception to December 2023. Screening, data extraction, and quality appraisal (AMSTAR 2) were done by two independent reviewers. Data were synthesised narratively and quantitatively. Relative risks (RR)/odds ratio (OR) with 95% confidence intervals were reported.

RESULTS

Thirty-two reviews were included consisting of 709 primary studies. The review reported the association between 12 autoimmune conditions and 16 adverse pregnancy outcomes. Higher risk of miscarriage is reported in women with Sjögren's syndrome RR 8.85 (95% CI 3.10-25.26) and systemic lupus erythematosus (SLE) OR 4.90 (3.10-7.69). Pre-eclampsia was reported higher in women with type 1 diabetes mellitus (T1DM) OR 4.19 (3.08-5.71) and SLE OR 3.20 (2.54-4.20). Women reported higher risk of diabetes during pregnancy with inflammatory bowel disease (IBD) OR 2.96 (1.47-5.98). There was an increased risk of intrauterine growth restriction in women with systemic sclerosis OR 3.20 (2.21-4.53) and coeliac disease OR 1.71 (1.36-2.14). Preterm birth was associated with T1DM OR 4.36 (3.72-5.12) and SLE OR 2.79 (2.07-3.77). Low birth weight babies were reported in women with women with SLE or systemic sclerosis OR 5.95 (4.54-7.80) and OR 3.80 (2.16-6.56), respectively. There was a higher risk of stillbirth in women with T1DM OR 3.97 (3.44-4.58), IBD OR 1.57 (1.03-2.38), and coeliac disease OR 1.57 (1.17-2.10). T1DM in women was associated with 32% lower odds of small for gestational age baby OR 0.68 (0.56-0.83).

CONCLUSIONS

Pregnant women with autoimmune conditions are at a greater risk of developing adverse pregnancy outcomes. Further research is required to develop better preconception to postnatal care for women with autoimmune conditions.

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.

Are there bidirectional associations between maternal thyroid function and glucose metabolism in singleton live births? A birth cohort study

(1) Aims: To examine the associations between maternal thyroid function and glucose metabolism during pregnancy. (2) Methods: This study was based on Ma' anshan Birth Cohort in China. Totally 2375 pregnant women were included in data analysis. Maternal thyroid-stimulating hormone (TSH), free thyroxine (FT4), thyroid peroxidase antibody (TPOAb) and fasting plasma glucose (FPG) levels during the first, second and third trimesters of pregnancy were measured retrospectively. Mplus 8.0 was used to construct a cross-lagged panel model to examine the potential bidirectional association between thyroid function and FPG levels throughout pregnancy. (3) Results: FT4 levels were positively correlated with FPG levels in the first trimester and negatively correlated with FPG levels in the second trimester. TSH levels were negatively associated with FPG levels in the second trimester, and in the first trimester, it could positively predict FPG levels in the second trimester. No significant association was found between TPOAb levels and FPG levels during pregnancy. (4) Conclusions: There was a non-bidirectional association between maternal thyroid function and glucose metabolism during pregnancy. FT4 and TSH levels influence FPG concentrations in the first and second trimesters of pregnancy.

Effects of treating subclinical hypothyroidism in pregnancy in India: Are we treating too many for little gain? A retrospective cohort study

OBJECTIVE

To assess the impact of treatment of subclinical hypothyroidism (SCH) on short-term pregnancy outcomes.

METHOD

Data from 4526 consecutive women with singleton pregnancies who delivered between January 2015 and December 2017 were analyzed. SCH was defined as a thyroid-stimulating hormone (TSH) level between 2.5 and 10 mU/mL with normal free thyroxine. Of those with SCH, some were treated but others were not. These two groups were compared using χ2 and Student t tests for categorical and continuous variables, respectively. Multiple logistic regression models, adjusted for maternal age, body mass index, parity, gestation at TSH measurement, and gestational diabetes mellitus status, were used to investigate the effect of treatment on pregnancy and neonatal outcomes.

RESULTS

In all, 1227 (27.1%) of 4526 women had SCH, of whom 393 (32.0%) were treated. The mean age and body mass index were similar in both groups. The mean gestation at measuring of TSH was 11.7 ± 6.5 weeks. There was no significant difference in pregnancy or neonatal outcomes between the two groups. A sub-group analysis when SCH was defined as TSH 4.0 mU/mL or greater showed a higher rate of large for gestational age and lower rates of low birth weight and small for gestational age in the treated group.

CONCLUSIONS

The prevalence of SCH based on the international guidelines threshold is high in India. Treatment of SCH did not show any difference in pregnancy and neonatal outcomes in this study.

Association of vitamin A with gestational diabetes and thyroid disorders in pregnancy and their influence on maternal, fetal, and neonatal outcomes

Gestational diabetes mellitus (GDM) and thyroid disorders during pregnancy pose significant health concerns, impacting a substantial number of mothers globally. Globally, about 14% of pregnant women develop GDM, while thyroid disorders impact approximately 2%-3%. Both conditions contribute to adverse outcomes, including gestational hypertension, excessive fetal growth, and heightened perinatal morbidity. The central focus of this literature review is to examine the relationship between vitamin A, a crucial fat-soluble micronutrient in fetal development, and the occurrence of GDM and thyroid disorders during pregnancy. The primary research question investigates the association between vitamin A, GDM, and thyroid disorders, analyzing their combined impact on maternal, fetal, and neonatal outcomes. The review underscores the potential of vitamin A to modulate the risk and outcomes of GDM and thyroid disorders during gestation, emphasizing its role in GDM development and resolution and its influence on thyroid function in pregnancy.

Optimizing levothyroxine treatment for subclinical hypothyroidism during pregnancy

The onset of pregnancy places additional stress of the thyroid gland, which must produce additional thyroid hormones to support the developing foetus. Hypothyroidism, including subclinical hypothyroidism (SCH), may appear de novo at this time, or existing thyroid disease may become more severe. Accordingly, SCH is a relatively common complication of up to about 3% of pregnancies, with higher rates in some areas. There is strong evidence from systematic reviews and meta-analyses that uncontrolled SCH is associated with an increased risk of adverse pregnancy outcomes, including miscarriage, preeclampsia, and gestational diabetes. The evidence base also suggests that treatment with levothyroxine (LT4), optimized to control thyrotropin (TSH) to within its pregnancy-specific reference ranges reduces these risks. Current management guidelines provide a clear framework of intervention with LT4 in pregnant women with SCH, especially where TSH is high or where thyroperoxidase autoantibodies are present. Sub-optimal adherence to LT4 is common: it is important that patients take their LT4 correctly and that treating physicians and/or healthcare professionals manage these patients according to the latest management guidelines. The titration of LT4 is likely to occur within a range of LT4 daily doses between 25 µg and 75 µg for the majority of this population. LT4 is a narrow therapeutic index drug and small variations in dosage may produce a clinically significant change in thyroid status. Newer formulations of LT4, engineered to provide more precise and consistent dosing, and with a broad range of tablet strengths, may facilitate the precise titration of the LT4 dose for these patients.

Prevalence and risk factors of gestational diabetes in the health region of Lleida: a retrospective observational cohort study

BACKGROUND

Diabetes is a very common metabolic condition during pregnancy. The number of cases increases with age and obesity. The prevalence of pre-gestational diabetes and gestational diabetes (GD) differs between different ethnic groups.

OBJECTIVE

The aim of the study was to analyse the prevalence of pre-gestational diabetes and GD in the health region of Lleida. We also studied the GD risk factors during pregnancy according to the country of origin of the pregnant woman.

METHODS

We performed a retrospective observational cohort study among pregnant women between 2012 and 2018 in the health region of Lleida. A multivariate model was performed with the different variables analysed by calculating the regression coefficient and its 95% confidence interval (CI).

RESULTS

In our sample of 17,177 pregnant women, we observed a prevalence of pre-gestational diabetes and GD of 8.2% and 6.5%, respectively. We found a relationship of gestational diabetes with different factors: age, with 6.8% in 30-34 year-old women and 11.3% in women over 35 (OR 1.78 and 3.29, respectively); overweight, with 8.29% (OR 1.89); and obesity, with 12.9% (OR 3.15). Finally, women from Asia and the Middle East and the Maghreb had a higher risk of diabetes, with 12.2% (OR 2.1) and 9.91% (OR 1.3), respectively, and Sub-Saharan women had a lower risk of it 6.07% (OR 0.71).

CONCLUSIONS

GD has different risk factors, such as age, overweight, and obesity. Non-related conditions include hypothyroidism, arterial hypertension, and dyslipidaemia. Finally, pregnant women from the Maghreb, and Asia and the Middle East, are at higher risk of developing diabetes during pregnancy; meanwhile, Sub-Saharan origin is protector factor.

Pre-pregnancy body mass index and glycated-hemoglobin with the risk of metabolic diseases in gestational diabetes: a prospective cohort study

Background

Metabolic diseases during pregnancy result in negative consequences for mothers. Pre-pregnancy body mass index (BMI) and late-pregnancy glycated-hemoglobin (HbA1c) are most important factors independently affecting the risk of gestational diabetes mellitus (GDM). However how both affect the combined risk of other metabolic diseases in women with GDM is unclear. The study aims to investigate the influence of pre-pregnancy BMI and pregnancy glycemic levels on other gestational metabolic diseases in women with GDM.

Methods

Pregnancies with GDM from January 2015 to December 2018 in the Xi'an longitudinal mother-child cohort study (XAMC) were retrospectively enrolled. Those without other metabolic diseases by the time of oral glucose tolerance test (OGTT) detection were finally recruited and divided into four groups by pre-pregnancy BMI (Underweight <18.5kg/m2; Normal weight 18.5-23.9 kg/m2; Overweight 24.0-27.9 kg/m2; Obesity ≥28.0 kg/m2, respectively) or two groups by HbA1c in late pregnancy (normal HbA1c<5.7%; high HbA1c≥5.7%). Multivariate logistic regression analysis was used to identify risk factors. Interaction between pre-pregnancy BMI (reference group 18.5-23.9 kg/m2) and HbA1c (reference group <5.7%) was determined using strata-specific analysis.

Results

A total of 8928 subjects with GDM were included, 16.2% of which had a composite of metabolic diseases. The pre-pregnancy overweight and obesity, compared with normal BMI, were linked to the elevated risk of the composite of metabolic diseases, particularly pre-eclampsia (both P <0.001) and gestational hypertension (both P <0.001). Meanwhile, patients with high HbA1c had an obvious higher risk of pre-eclampsia (P< 0.001) and gestational hypertension (P= 0.005) compared to those with normal HbA1c. In addition, there were significant interactions between pre-pregnancy BMI and HbA1c (P< 0.001). The OR of pre-pregnancy BMI≥ 28 kg/m2 and HbA1c≥ 5.7% was 4.46 (95% CI: 2.85, 6.99; P< 0.001). The risk of other metabolic diseases, except for pre-eclampsia (P= 0.003), was comparable between the two groups of patients with different HbA1c levels at normal pre-pregnancy BMI group. However, that was remarkably elevated in obese patients (P= 0.004), particularly the risk of gestational hypertension (P= 0.004).

Conclusion

Pre-pregnancy overweight/obesity and late-pregnancy high HbA1c increased the risk of other gestational metabolic diseases of women with GDM. Monitoring and controlling late-pregnancy HbA1c was effective in reducing metabolic diseases, particularly in those who were overweight/obese before conception.

Association of impaired sensitivity to thyroid hormones with hyperuricemia through obesity in the euthyroid population

BACKGROUND

Impaired sensitivity to thyroid hormones is a newly proposed clinical entity associated with hyperuricemia in the subclinical hypothyroid population. However, it is unknown whether the association exists in the euthyroid population. This study aimed to explore the association of impaired sensitivity to thyroid hormones (assessed by the thyroid feedback quantile-based index [TFQI], parametric thyroid feedback quantile-based index [PTFQI], thyrotrophic thyroxine resistance index [TT4RI] and thyroid-stimulating hormone index [TSHI]) with hyperuricemia and quantify the mediating effect of body mass index BMI in the euthyroid population.

METHODS

This cross-sectional study enrolled Chinese adults aged ≥ 20 years who participated in the Beijing Health Management Cohort (2008-2019). Adjusted logistic regression models were used to explore the association between indices of sensitivity to thyroid hormones and hyperuricemia. Odds ratios [OR] and absolute risk differences [ARD] were calculated. Mediation analyses were performed to estimate direct and indirect effects through BMI.

RESULTS

Of 30,857 participants, 19,031 (61.7%) were male; the mean (SD) age was 47.3 (13.3) years; and 6,515 (21.1%) had hyperuricemia. After adjusting for confounders, individuals in the highest group of thyroid hormone sensitivity indices were associated with an increased prevalence of hyperuricemia compared with the lowest group (TFQI: OR = 1.18, 95% CI 1.04-1.35; PTFQI: OR = 1.20, 95% CI 1.05-1.36; TT4RI: OR = 1.17, 95% CI 1.08-1.27; TSHI: OR = 1.12, 95% CI 1.04-1.21). BMI significantly mediated 32.35%, 32.29%, 39.63%, and 37.68% of the associations of TFQI, PTFQI, TT4RI and TSHI with hyperuricemia, respectively.

CONCLUSIONS

Our research revealed that BMI mediated the association between impaired sensitivity to thyroid hormones and hyperuricemia in the euthyroid population. These findings could provide useful evidence for understanding the interaction between impaired sensitivity to thyroid hormone and hyperuricemia in euthyroid individuals and suggest the clinical implications of weight control in terms of impaired thyroid hormones sensitivity.

Subclinical hypothyroidism, outcomes and management guidelines: a narrative review and update of recent literature

Subclinical hypothyroidism (SCH) is diagnosed when serum thyroid stimulation hormone (thyrotropin; TSH) levels are above the reference range, accompanied by levels of free thyroxine within its reference range. The management of SCH remains a diagnostic and therapeutic challenge despite many years of research relating to its epidemiology, aetiology, effectiveness of treatment and safety. European Thyroid Association (ETA) guidelines for the management of SCH were published almost a decade ago. This narrative review summarizes the clinical literature relating to SCH and outcomes since the publication of these guidelines. Clinical evidence emerging during the previous decade generally supports the view that SCH is associated with adverse outcomes to an extent that is intermediate between euthyroidism and overt hypothyroidism although evidence that treatment with thyroid hormone replacement is beneficial is lacking. Accordingly, the rationale for the recommendations for intervention in the ETA guidelines based on the age of the patient, level of serum TSH, symptoms and comorbidities remains valid today.

Evaluation of first and second trimester maternal thyroid profile on the prediction of gestational diabetes mellitus and post load glycemia

Maternal thyroid alterations have been widely associated with the risk of gestational diabetes mellitus (GDM). This study aims to 1) test the first and the second trimester full maternal thyroid profile on the prediction of GDM, both alone and combined with non-thyroid data; and 2) make that prediction independent of the diagnostic criteria, by evaluating the effectiveness of the different maternal variables on the prediction of oral glucose tolerance test (OGTT) post load glycemia. Pregnant women were recruited in Concepción, Chile. GDM diagnosis was performed at 24-28 weeks of pregnancy by an OGTT (n = 54 for normal glucose tolerance, n = 12 for GDM). 75 maternal thyroid and non-thyroid parameters were recorded in the first and the second trimester of pregnancy. Various combinations of variables were assessed for GDM and post load glycemia prediction through different classification and regression machine learning techniques. The best predictive models were simplified by variable selection. Every model was subjected to leave-one-out cross-validation. Our results indicate that thyroid markers are useful for the prediction of GDM and post load glycemia, especially at the second trimester of pregnancy. Thus, they could be used as an alternative screening tool for GDM, independently of the diagnostic criteria used. The final classification models predict GDM with cross-validation areas under the receiver operating characteristic curve of 0.867 (p<0.001) and 0.920 (p<0.001) in the first and the second trimester of pregnancy, respectively. The final regression models predict post load glycemia with cross-validation Spearman r correlation coefficients of 0.259 (p = 0.036) and 0.457 (p<0.001) in the first and the second trimester of pregnancy, respectively. This investigation constitutes the first attempt to test the performance of the whole maternal thyroid profile on GDM and OGTT post load glycemia prediction. Future external validation studies are needed to confirm these findings in larger cohorts and different populations.

Can Thyroid Screening in the First Trimester Improve the Prediction of Gestational Diabetes Mellitus?

This study aimed to evaluate the clinical utility of the subclinical hypothyroidism (SCH) marker, elevated thyroid-stimulating hormone (TSH) and thyroid antibodies in their ability to predict subsequent gestational diabetes mellitus (GDM). In a prospective clinical trial, 230 pregnant women were screened for thyroid function during the first trimester of pregnancy. Increased TSH levels with normal free thyroxine (fT4) were considered SCH. The titers of thyroid peroxidase antibody (anti TPO Ab) at >35 IU/mL and thyroglobulin antibody (anti Tg Ab) at >115 IU/mL were considered as antibodies present. According to the OGTT results, the number of pregnant women with GDM showed the expected growth trend, which was 19%. Two groups of pregnant women were compared, one with GDM and the other without. Increased TSH levels and the presence of thyroid antibodies showed a positive correlation with the risk of GDM. TSH levels were significantly higher in pregnant women with GDM, p = 0.027. In this study, 25.6% of pregnant women met the diagnostic criteria for autoimmune thyroiditis. Hashimoto’s thyroiditis was significantly more common in GDM patients, p < 0.001. Through multivariate logistic regression, it was demonstrated that patient age, TSH 4 IU/mL, and anti TPO Ab > 35 IU/mL are significant predictors of gestational diabetes mellitus that may improve first-trimester pregnancy screening performance, AUC: 0.711; 95% CI: 0.629−0.793.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Untreated thyroid autoantibody-negative SCH increases the risk of spontaneous abortions

BACKGROUND

Numerous studies have found that subclinical hypothyroidism (SCH) may increase adverse pregnancy outcomes; however, the benefit of levothyroxine (LT4) treatment remains controversial. The 2017 guidelines of the American Thyroid Association weakly recommended LT4 therapy for serum antithyroid peroxidase antibody (TPOAb)-negative women with thyroid-stimulating hormone (TSH) concentrations greater than the pregnancy-specific reference range and below 10.0 mU/L. Therefore, the primary goal of this study was to investigate the correlation between thyroid autoantibody-negative SCH with or without LT4 treatment and adverse pregnancy outcomes.

METHODS

We prospectively enrolled 1868 consecutive pregnant women. Finally, 1344 women were involved in the study according to the inclusion and exclusion criteria. Assays for TSH, free thyroxine (FT4), TPOAb, anti-thyroglobulin antibody, and laboratory indicators were performed. The participants were divided into the euthyroid (ET) group (n = 1250) and the SCH group(n = 94). The SCH group was further divided into LT4 group (n = 40) and non-LT4 group(n = 54). The laboratory indicators and pregnancy outcomes were evaluated during follow-ups.

RESULTS

Maternal age, BMI, parity, and the history of spontaneous abortion did not differ significantly between the ET group and the different SCH groups. There were no significant differences in lipid profile and homocysteine levels between ET and SCH group in the first and third trimester of pregnancy. After adjusting the confounding factors, the non-LT4 group was a risk factor for spontaneous abortion (odds ratio: 3.141, 95% CI: 1.060-9.302). Survival analysis showed that the time of abortion was different between the ET group and SCH group (log-rank P= 0.042). The spontaneous abortion in SCH, especially in non-LT4, group mainly occurred in the first trimester of pregnancy.

CONCLUSIONS

Thyroid autoantibody negative-SCH seems to be associated with increased risk of spontaneous abortions during the first trimester of pregnancy. LT4 therapy in this patient population might be beneficial to reduce adverse pregnancy outcomes.

Correlation Between Hypothyroidism During Pregnancy and Glucose and Lipid Metabolism in Pregnant Women and Its Influence on Pregnancy Outcome and Fetal Growth and Development

Purpose:

To observe the correlation between hypothyroidism during pregnancy and glucose and lipid metabolism in pregnant women and its influence on a pregnancy outcome and fetal growth and development.

Methods

About 152 patients with hypothyroidism during pregnancy in our hospital from June 2017 to June 2020 were selected as the observation group and divided into the overt hypothyroidism (OH) group, the subclinical hypothyroidism (SCH) group, and the low T4 group. Another 60 pregnant women with normal antenatal examination and normal thyroid function were selected as the normal group. The glucose and lipid metabolism indexes of each group were compared. The pregnant women in the OH group and the SCH group were given levothyroxine intervention, and the pregnancy outcome and infant development of the two groups were compared.

Results

The fasting blood glucose and hemoglobin A1c, triglyceride and low-density lipoprotein of the OH group and the SCH group were higher than the low T4 group and the normal group, and the OH group was higher than the SCH group (p &lt; 0.05). The incidence of premature delivery and premature rupture of membranes at term (PROM at term) in the hypothyroidism non-control group was higher than the hypothyroidism control group (p &lt; 0.05). The mental development index and the psychomotor development index in the hypothyroidism non-control group were lower than the hypothyroidism control group (p &lt; 0.05).

Conclusion

Pregnant women with hypothyroidism during pregnancy are more prone to glucose and lipid metabolism disorder, which increases the risk of premature delivery and PROM at term, and has certain influence on the intellectual development and psychomotor development of infants.

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.

sCD40L Is Increased and Associated with the Risk of Gestational Diabetes Mellitus in Pregnant Women with Isolated TPOAb Positivity

BACKGROUND

Autoimmune disorders are associated with gestational diabetes mellitus (GDM) in pregnant women who were positive for thyroid peroxidase antibody (TPOAb). Soluble CD40 ligand (sCD40L) and soluble interleukin-2 receptor (sCD25) are abnormally expressed in autoimmune diseases and are reliable markers of inflammation. The purpose of this study was to evaluate sCD40L and sCD25 in early pregnancy and investigate their correlation with GDM and TPOAb.

METHODS

A total of 126 pregnant women in the first trimester were enrolled for analysis: 93 were positive for TPOAb and 33 were negative for TPOAb. Demographical and clinical data in early pregnancy were collected. A total of 123 participants underwent a 75 g oral glucose tolerance test in the second trimester. Serum sCD40L and sCD25 levels were measured by ELISA.

RESULTS

The incidence of GDM was 24.4% in pregnant women with isolated TPOAb positivity in our study. Both sCD40L and sCD25 were positively correlated with TPOAb (r = 0.476, P < 0.001; r = 0.188, P < 0.05). sCD40L was highest in (P < 0.001) Ab-positive women with GDM group (P < 0.05). After adjusting for TPOAb, age, TSH, FT4, triglycerides, and low-density lipoprotein cholesterol, multivariate logistic regression analysis showed that sCD40L was an independent risk factor for GDM in pregnant women with TPOAb positivity (odds ratio = 3.235, 95% confidence interval 1.024-10.218, P < 0.05).

CONCLUSIONS

About a quarter of pregnant women with isolated positive TPOAb might have GDM. sCD40L was an independent risk factor for GDM in women with isolated TPOAb positivity.

Increased Central and Peripheral Thyroid Resistance Indices During the First Half of Gestation Were Associated With Lowered Risk of Gestational Diabetes-Analyses Based on Huizhou Birth Cohort in South China

OBJECTIVES

The study aimed to explore the relationship of thyroid function and resistance indices with subsequent risk of gestational diabetes (GDM).

DESIGN

This was a longitudinal study embedded in the Huizhou Birth Cohort.

METHODS

A total of 2,927 women of singleton pregnancy were recruited from January to October of 2019. Thyroid central resistance indices were evaluated by Thyroid Feedback Quartile-Based index (TFQI), Thyrotrophy T4 Resistance Index (TT4RI), and TSH Index (TSHI) based on plasma-free thyroxine (FT4) and thyroid-stimulating hormone (TSH) levels during the first half of pregnancy. Thyroid peripheral sensitivity was assessed by free triiodothyronine (FT3) to FT4 ratio (FT3/FT4), a proxy of deiodinase activity. GDM was diagnosed between 24 and 28 weeks of gestation by a standardized 75 g oral glucose tolerance test. Multivariable linear and logistic regression was applied to examine the associations of thyroid markers with GDM risk.

RESULTS

FT3 and FT3/FT4 were positively associated with both fasting and post-load glucose levels, while TSH, TSHI, TT4RI, and TFQI were negatively associated with 1 and 2 h post-load glucose levels. Compared with the lowest quartile, GDM risk in the highest quartile increased by 44% [odds ratio (OR) = 1.44; 95%CI, 1.08-1.92; p_trend = 0.027] for FT3 and 81% (OR = 1.81; 95%CI, 1.33-2.46; p_trend < 0.001) for FT3/FT4, while it lowered by 37% (OR = 0.63; 95%CI, 0.47-0.86; p_trend = 0.002] for TSHI, 28% for TT4RI (OR = 0.72; 95%CI, 0.54-0.97; p_trend = 0.06), and 37% for TFQI (OR = 0.63; 95%CI, 0.46-0.85; p_trend < 0.001).

CONCLUSIONS

This longitudinal study indicated that higher FT3 and FT3/FT4 and lower central thyroid resistance indices were associated with increased risk of GDM.

A Novel Nomogram for Predicting Gestational Diabetes Mellitus During Early Pregnancy

Objective

Gestational diabetes mellitus (GDM) is a serious threat to maternal and child health. However, there isn't a standard predictive model for the disorder in early pregnancy. This study is to investigate the association of blood indexes with GDM and establishes a practical predictive model in early pregnancy for GDM.

Methods

This is a prospective cohort study enrolling 413 pregnant women in the department of Obstetrics and Gynecology in Shanghai General Hospital from July 2020 to April 2021.A total of 116pregnantwomen were diagnosed with GDM during the follow-up. Blood samples were collected at early trimester (gestational weeks 12-16) and second trimester(gestational weeks 24-26 weeks). A predictive nomogram was established based on results of the multivariate logistic model and 5-fold cross validation. We evaluate the nomogram by the area under the receiver operating characteristic curve (AUC), calibration curves and decision curve analysis (DCAs).

Results

Significant differences were observed between the GDM and normal controls among age, pre-pregnancy BMI, whether the pregnant women with complications, the percentage of B lymphocytes, fasting plasma glucose (FPG), HbA1c, triglyceride and the level of progesterone in early trimester. Risk factors used in nomogram included age, pre-pregnancy BMI, FPG, HbA1c, the level of IgA, the level of triglyceride, the percentage of B lymphocytes, the level of progesterone and TPOAb in early pregnancy. The AUC value was 0.772, 95%CI (0.602,0.942). The calibration curves for the probability of GDM demonstrated acceptable agreement between the predicted outcomes by the nomogram and the observed values. DCA curves showed good positive net benefits in the predictive model.

Conclusions

A novel predictive nomogram was developed for GDM in our study, which could do help to patient counseling and management during early pregnancy in clinical practice.

Is the link between elevated TSH and gestational diabetes mellitus dependant on diagnostic criteria and thyroid antibody status: a systematic review and meta-analysis

PURPOSE

Clinical studies have investigated the prevalence of gestational diabetes mellitus (GDM) in women with subclinical hypothyroidism (SCH). While some studies demonstrate a clear association, others do not. It is possible this may be due to varied diagnostic criteria for SCH and the presence of thyroid antibodies (TA). We conducted a meta-analysis, separating patients diagnosed with SCH using a diagnostic cut-off <4.0 mIU/L from those diagnosed using a cut-off >4.0 mIU/L and determined the association with GDM and factored TA status into our analysis.

METHODS

A computerised search of five databases including PubMed, Embase, Cochrane Library, Web of Science and CINAHL returned 787 records. Two independent reviewers assessed abstracts and full texts against pre-specified inclusion and exclusion criteria. Ten cohort studies were included in the final analysis. The diagnostic criteria for SCH and incidence of GDM were extracted from each study. Study quality and risk of bias was assessed by two reviewers.

RESULTS

TSH levels <4.0 mIU/L for SCH diagnosis was not associated with GDM unless patients were TA positive. Studies that used a diagnostic cut-off >4.0 mIU/L saw a significant increase in the odds of GDM, regardless of TA status (OR = 1.60, 95% CI 1.33-1.93).

CONCLUSIONS

Women with TSH levels >4.0 mIU/L have an increased odds of GDM regardless of TA status but at TSH levels <4.0 mIU/L, GDM is dependent on TA status. The use of TSH levels to identify pregnancies at risk of GDM is a novel concept that warrants exploration.

A pathway level analysis of PFAS exposure and risk of gestational diabetes mellitus

Per- and polyfluoroalkyl substances (PFAS) have been found to be associated with gestational diabetes mellitus (GDM) development, a maternal health disorder in pregnancy with negative effects that can extend beyond pregnancy. Studies that report on this association are difficult to summarize due to weak associations and wide confidence intervals. One way to advance this field is to sharpen the biologic theory on a causal pathway behind this association, and to measure it directly by way of molecular biomarkers. The aim of this review is to summarize the literature that supports a novel pathway between PFAS exposure and GDM development. Epidemiological studies demonstrate a clear association of biomarkers of thyroid hormones and glucose metabolism with GDM development. We report biologic plausibility and epidemiologic evidence that PFAS dysregulation of maternal thyroid hormones and thyrotropin (TSH) may disrupt glucose homeostasis, increasing the risk of GDM. Overall, epidemiological studies demonstrate that PFAS were positively associated with TSH and negatively with triiodothyronine (T3) and thyroxine (T4). PFAS were generally positively associated with glucose and insulin levels in pregnancy. We propose dysregulation of thyroid function and glucose metabolism may be a critical and missing component in the accurate estimation of PFAS on the risk of GDM.

A longitudinal study of thyroid markers during pregnancy and the risk of gestational diabetes mellitus and post-partum glucose metabolism

AIMS

To determine the relationship between thyroid markers during pregnancy and gestational diabetes mellitus (GDM) or post-partum glucose metabolism.

MATERIALS AND METHODS

Based on pregnancy 75-g oral glucose tolerance test (OGTT) results, 1467 subjects were grouped into normal glucose tolerance (NGTp; n = 768) and GDM (n = 699) groups. Furthermore, based on post-partum 75-g OGTT results, 286 GDM subjects, screened for glucose metabolism after delivery, were grouped into NGTd (n = 241) and abnormal glucose tolerance (AGT; n = 45) groups.

RESULTS

Maternal age, family history of diabetes, acanthosis nigricans, previous adverse pregnancy outcomes and caesarean section incidence, and thyroid positive antibody rates were higher in the GDM group than in the NGTp group. In the first trimester, free triiodothyronine (FT3), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb) levels were higher in the GDM group than in the NGTp group. In the second trimester, free thyroxine (FT4) levels were lower and TPOAb and TgAb levels were higher in the GDM group than in the NGTp group. After adjusting for confounding factors, FT3, TPOAb and TgAb (first trimester), and FT4, TPOAb and TgAb (second trimester) were risk factors for GDM. TPOAb and TgAb levels were higher in the AGT group than in the NGTd group and were potential predictors of abnormal post-partum glucose tolerance.

CONCLUSIONS

GDM risk significantly increased with increased FT3 (first trimester), TPOAb and TgAb (first and second trimesters) or with decreased FT4 (second trimester). Presence of thyroid antibodies predicted post-partum glucose abnormalities in subjects with GDM.

Impact of Early Pregnancy Subclinical Hypothyroidism on Gestational Diabetes Mellitus: A Retrospective Study of 7,536 Cases

Background: Maternal subclinical hypothyroidism (SCH) has been associated with adverse pregnancy outcomes. This study aimed to explore whether SCH in the first trimester contributed to the development of gestational diabetes mellitus (GDM). Materials and Methods: A total of 8,777 pregnant women who first visited before 13 weeks and 6 days of gestation and accepted routine prenatal service at the Third Affiliated Hospital of Sun Yat-Sen University from January 2015 to September 2018 were recruited in this study. Thyroid functions (thyroid stimulating hormone [TSH], free T4, and thyroid peroxidase antibody [TPOAb]) were measured before 13 weeks and 6 days of gestation and data of 7,536 subjects with TSH ≥0.1 mIU/L were analyzed. A 2-hour 75-g oral glucose tolerance test was performed between 24 and 28 gestational weeks. Chi-square test and multivariate logistic regression analysis were applied to evaluate the relationship between SCH and GDM. Results: The prevalence of SCH in this population was 7.53%. After stratifying the relationship between SCH and GDM according to TSH concentrations (slightly elevated TSH: ≥2.5, <4.0 mIU/L; moderately elevated TSH: ≥4.0, <10.0 mIU/L) and TPOAb status, a moderately elevated TSH combined with positive TPOAb (23.9% vs. normal 13.0%, chi-square = 6.317, p = 0.012) was found to increase the incidence of GDM. Furthermore, after adjusting for confounders (maternal age, educational levels, parity, and pregestational body mass index [preBMI]), the SCH group still exhibited a higher risk of GDM (relative risk [RR] 1.867, 95% confidence interval [CI] 1.018-3.424). Conclusion: Our findings indicated that SCH during early pregnancy, in the presence of moderately elevated TSH levels and positive TPOAb, might lead to an increased risk of GDM.

Different Gestational Diabetes Phenotypes: Which Insulin Regimen Fits Better?

OBJECTIVE

Maternal characteristics and OGTT values of pregnancies complicated by gestational diabetes mellitus (GDM) were evaluated according to treatment strategies. The goal was to identify different maternal phenotypes in order to predict the appropriate treatment strategy.

METHODS

We conducted a retrospective study among 1,974 pregnant women followed up for GDM in a tertiary referral hospital for high-risk pregnancies (Careggi University Hospital, Florence, Italy) from 2013 to 2018. We compared nutritional therapy (NT) alone (n = 962) versus NT and insulin analogues (n = 1,012) group. Then, we focused on different insulin analogues groups: long acting (D), rapid acting (R), both D and R. We compared maternal characteristics of the three groups, detecting which factors may predict the use of rapid or long-acting insulin analogue alone versus combined therapy.

RESULTS

Among women included in the analysis, 51.3% of them needed insulin therapy for glycemic control: 61.8% D, 28.3% combined D and R, and 9.9% R alone. Age >35 years, pre-pregnancy BMI >30, family history of diabetes, previous GDM, altered fasting plasma glucose (FPG), hypothyroidism, and assisted reproductive technologies (ART) were identified as maternal variables significantly associated with the need of insulin therapy. Altered 1-h and 2-h glucose plasma glucose level at OGTT, age >35 years, and previous GDM were found as independent predicting factors for the use of combined therapy with rapid and long acting analogues for glycemic control. On the contrary, pre-pregnancy BMI <25 and normal fasting plasma glucose values at OGTT were found to be significantly associated to the use of rapid insulin analogue only.

CONCLUSION

A number of maternal and metabolic variables may be identified at the diagnosis of GDM, in order to identify different GDM phenotypes requiring a personalized treatment for glycemic control.

Is There Any Relationship Between Thyroid Function Abnormalities, Thyroid Antibodies and Development of Gestational Diabetes Mellitus (GDM) in Pregnant Women?

Objective

To determine the levels of thyroid-stimulating hormone (TSH), thyroxin (T4), triiodothyronine (T3), anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-TG) and renal iodine excretion (RIE) in the first trimester of the pregnancy and to estimate the risk of developing GDM in these patients.

Method

The levels of TSH, T3, T4, anti-TPO, anti-TG, and RIE were retrospectively evaluated. A total of 312 pregnant women were included in the study (GDM (-) group n=240, GDM (+) group n=62). Diagnosis of GDM was made according to the recommendation of American Diabetes Organization (ADA). The association between thyroid dysfunction and GDM was evaluated.

Results

Our study included a total of 302 women. Sixty-two of these women were diagnosed as GDM (62/302=20.5%). When compared with the GDM (-) group the mean TSH level (2.02 vs 4.13 p=0.019), anti-TPO positivity (8.3% vs 30.64% p=0.044), anti-TG positivity (8.3% vs 19.4% p=0.019) and RIE (156 vs 178 p=0.017) were significantly higher in the GDM (+) group. TSH levels were statistically significantly higher in patients with positive anti-TPO levels (P=0.045).

Conclusion

Elevated TSH levels , TPO and TG antibody positivity rates were more frequent among the patients with GDM. These results may be a guide to perform routine thyroid function tests for patients with increased risk of GDM, on the other hand, they will alert the physicians for GDM progression and ensure taking preventive attempts for the patients who have thyroid disorder, especially those with positive thyroid antibodies in the first trimester of the pregnancy.

Risk factors associated with gestational diabetes mellitus: The role of pregnancy-induced hypertension and physical inactivity

BACKGROUND

Gestational diabetes mellitus (GDM) causes serious complications affecting the mother and fetus. Physical activity (PA) during pregnancy has positive effects on the mother and fetus. The objectives of this study were to assess GMD prevalence in Kuwait, identify its risk factors, and to evaluate its association with PA.

METHODS

A cross-sectional study was conducted among a randomly selected 653 post-partum women from all public maternal centers and five private centers. An anonymous self-administered questionnaire was used to collect participants' socio-demographic data, medical and obstetric history. Pregnancy Physical Activity Questionnaire (PPAQ) was used to assess PA level.

RESULTS

Participants' mean age was 30.1 ± 5.3. GMD was diagnosed among 14.1% (95% CI: 11.6-17.0) of participants. Binary logistic regression revealed that poor income, having 2 + chronic diseases, past history of GDM, hypothyroidism, high systolic or diastolic blood pressure during pregnancy were independently correlated with developing GDM. For physical activity, the overall means of PPAQ total and sub-scores were below average and only PPAQ sub-score -Vigorous Intensity Activity- was significantly higher amid women without GMD than those with. However, PPAQ mean scores showed significant positive correlation with women's pre-pregnancy BMI and birth weight; and a significant negative association with gestational systolic and diastolic blood pressure.

CONCLUSIONS

GDM prevalence is relatively high in Kuwait, notably amid expatriates. Pregnancy-induced hypertension along with social and pre-pregnancy medical conditions correlated with developing GDM. PA helped mitigated pregnancy blood pressure, and fetal birth weight. Promoting additional medical monitoring and PA during pregnancy might aid reduce the prevalence of GDM.