Thyroid Dysfunction in Pregnant Women with Gestational Diabetes Mellitus

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.

Subklinik Hipotiroidizm ile Gestasyonel Diabetes Mellitus Arasındaki İlişki

Amaç: Gebelikte en sık görülen metabolik bozukluk gestasyonel diyabetes mellitustur (GDM). GDM prevalansı yüzde 1,7 ile yüzde 11,6 arasında değişmektedir. Hipotiroidizmde glukoz oksidasyonu ve glikojen sentezi hızları azalır ve periferik dokularda glukoz kullanımı yavaşlar. Subklinik ve aşikar hipotiroidili hastalarda insülin direnci gelişir çünkü insülin kasların glikoz kullanımını yeterince sürdüremez. Literatüre göre, hipotiroidizm GDM gebeliklerinin yüzde 6-15'i ile bağlantılıdır. Ayrıca hipotiroidisi olan gebelerde GDM olma olasılığı 4,3 kat daha fazladır. Bu çalışma birinci trimester tiroid fonksiyon testleri ile GDM arasındaki ilişkiyi ortaya koymayı amaçlamıştır. Gereç ve Yöntem: Bu retrospektif kohort çalışma Mayıs 2021 ile Mayıs 2022 tarihleri ​​arasında yapıldı. Çalışmaya GDM tanısı konan 100 gebe hasta ve 500 sağlıklı kontrol dahil edildi. GDM, 75 g glikoz yükleme testi kullanılarak teşhis edildi. TSH ve sT4 değerleri trimestere göre kabul edilen normal sınırlara göre değerlendirildi. Bulgular: GDM olan ve olmayan hastalar arasında SKH açısından istatistiksel olarak anlamlı fark vardı (p=0.04). AUC ve ROC, TSH'nin GDM'yi öngörme performansını değerlendirmek için kullanıldı (AUC=0.586 ve p=0.006). GDM'yi öngörmek için TSH düzeyi cut-off değeri 1.58 olarak belirlendi. AUC'nin 0,586 (0,521-0,652) olduğu bulundu. Ayrıca seçicilik %58 ve duyarlılık %41'dir. Sonuç: Literatürde tiroid fonksiyonlarını ve gestasyonel diabetes mellitus gelişimini araştıran birçok çalışma bulunmaktadır. Bizim çalışmamızda da birinci trimesterde subklinik hipotiroidi tanısı ile GDM arasında ilişki bulundu. Çalışma, birinci trimester tiroid fonksiyon testi sonuçlarına dayanarak, gestasyonel diyabetes mellitus gelişimi açısından dikkatli ve uyanık olmanın önemini literatüre katmaktadır.

Subsequent perinatal outcomes of pregnancy with two consecutive pregnancies with gestational diabetes mellitus: A population-based cohort study

BACKGROUND

Gestational diabetes mellitus (GDM) is glucose intolerance diagnosed during pregnancy. We aimed to explore the different outcomes of women with two consecutive pregnancies with GDM.

METHODS

This study included 861 women with recurrent GDM who had two consecutive singleton deliveries at Fujian Maternity and Child Health Hospital between May 2012 and September 2020. Data on pregnancy complications and neonatal and delivery outcomes were collected and analyzed.

RESULTS

Among those women with recurrent GDM, there was no difference in pregnancy complications in index pregnancy vs subsequent pregnancy. Our data revealed there was a significantly higher incidence of thyroid disease in the subsequent pregnancies than in the index pregnancy. (6% vs 10%, p = .003)In subsequent pregnancies, the birth weight was greater than that of the index pregnancy (3296.63 ± 16.85 vs 3348.99 ± 16.05, p = .025); and the incidence of large for gestational age (LGA) was higher than that of the index pregnancy (16.3% vs 20.6%, p = .021). More cesarean sections occurred in the subsequent pregnancy. (32.9% vs 6.6%, p = .039). Postpartum hemorrhage, premature birth, and placental abruption were not significantly different between the two pregnancies.

CONCLUSIONS

The results suggest the effect of GDM on thyroid dysfunction may be persistent. Recurrent gestational diabetes results in a higher rate of cesarean delivery, incidence of LGA, and neonatal admission to the neonatal intensive care unit (NICU) in subsequent pregnancies. We need to pay attention to the postpartum thyroid function of pregnant women with GDM. Further studies are still needed on recurrent GDM to reduce this occurrence of admission to NICU.

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.

Assessment of the simultaneous effect of hypothyroidism and thyroid autoimmunity with gestational diabetes on the incidence of type 2 diabetes

INTRODUCTION

Despite the evidence available on the adverse impact of gestational diabetes (GDM) and thyroid disorders on developing type 2 diabetes (T2DM), the concurrent influence of these disorders on the incidence of T2DM has not been reported yet.

METHODS

In this prospective study, 1894 non-diabetic women aged 20 to 60 years, with a history of at least one term delivery, without diagnosed hyperthyroidism were selected at the initiation of the Tehran Thyroid Study (TTS). Pooled logistic regression analyses were used to investigate the association of GDM, thyroid disorders i.e., hypothyroidism and/or thyroid peroxidase antibody (TPOAb) positivity and interaction between GDM and thyroid disorders with the risk of incident T2DM.

RESULTS

Of the 1894 participants of the present study, 346 (18.3%) had a history of GDM, and 832 (43.9%) had thyroid disorders. The total cumulative incidence rate of T2DM at the median follow-up time of ~ 12 years was overall 12/1000 person-years (95% confidence interval (CI): 10/1000-13/1000), with an incidence rate of 16/1000 (95%CI: 13/1000-20/1000) in women with GDM; and 11/100,000 (95%CI: 9/100,000-12/1000) among those without GDM. After adjustment for age, the risk of incident T2DM increased among individuals with the previous GDM compared to women without a history of GDM (odds ratio (OR): 1.54, 95%CI: 1.06, 2.25). No significant associations were found between either thyroid disorders or the interaction between GDM and thyroid disorders with the development of T2DM; (OR: 1.14, 95%CI: 0.82, 1.58) and (OR: 1.27, 95%CI: 0.66, 2.43), respectively.

CONCLUSION

GDM and thyroid disorders have no concurrent impacts on the incidence of T2DM.

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.