Prevalence of Thyroid Peroxidase Antibody and Pregnancy Outcome in Euthyroid Autoimmune Positive Pregnant Women from a Tertiary Care Center in Haryana

Raised First Trimester Thyroid Peroxidase Antibodies May Predict First Trimester Miscarriage: A Case Control Study

Miscarriages constitute a significant aspect of failed pregnancies and a source of worry for the patient and caregiver. Some of the causes of miscarriages remain unknown. Immunological conditions such as thyroid autoimmunity could play significant roles. Our objective was to determine the relationship between raised thyroid peroxidase antibodies and first trimester miscarriages in a low resource setting. This was a case control study at the Gynaecological Clinic of the University of Calabar Teaching Hospital, Nigeria; from 14th February 2020 to 13th January 2021, involving 145 cases who had first trimester miscarriages, and their matched controls who had apparently normal pregnancies, at same gestational ages. Sera of venous blood from both participants and controls were analysed for thyroid peroxidase antibodies using enzyme-linked immunosorbent assay, and analysed using SPSS version 20, and GraphPad Prism 8.4.3 statistical software. Being a civil servant and low social status had significant odds for first trimester miscarriage. Raised thyroid peroxidase antibodies in the first trimester had 10-fold odds for miscarriage. Odds ratio 10.34, 95% CI: 3.22 to 32.98, P-value = 0.0001. The test had a sensitivity of 89.66% and specificity of 54.41%. The positive predictive value was 17.93%, while the negative predictive value was 97.93% and a likelihood ratio of 1.966. Rising thyroid peroxidase antibodies in early pregnancy could be a predictor for miscarriage. This is so because patients with raised thyroid peroxidase antibodies in the first trimester had a 10-fold risk of having a first trimester miscarriage.

Influence of thyroid autoimmunity at various clinical stages of hypothyroidism on the risk of miscarriage before 20 weeks of gestation

PURPOSE

We aimed to clarify the influence of thyroid autoantibodies at various clinical stages of hypothyroidism on the risk of pregnancy loss before 20 weeks of gestation.

METHODS

We enrolled 230 pregnant women with a history of recurrent miscarriage. Detailed clinical history, physical examination, and laboratory testing of thyroid function, antithyroid peroxidase (anti-TPO), and antithyroglobulin (anti-TG) were applied among all participants.

RESULTS

Coexisting overt hypothyroidism and positive thyroid autoantibodies quadrupled the risk of miscarriage in women before 20 weeks of gestation (OR 4.04, 95% CI = 2.08-7.96, P < 0.001). Women with subclinical hypothyroidism (OR 1.44, 95% CI = 0.81-2.57, P = 0.132,) or who were euthyroid (OR 1.53, 95% CI = 0.86-2.73, P = 0.094) showed a non-significant risk of miscarriage even with positive thyroid autoantibodies. Thyroid-stimulating hormone (TSH) was positively correlated with the number of miscarriages rather than anti-TPO (P < 0.001 and 0.209, respectively).

CONCLUSION

Coexistence of overt hypothyroidism and thyroid autoimmunity was the only significant driver of pregnancy loss before 20 weeks of gestation.

Maternal thyroid peroxidase antibody positivity and its association with incidence of low birth weight in infants

Background

Autoimmune thyroid disease is a prevalent condition affecting women of reproductive age, leading to thyroid dysfunction and impacting pregnancy outcomes. While the critical role of thyroid hormone in pregnancy outcomes is well-established, the potential association between positive anti-thyroid peroxidase antibodies (TPOAb) and adverse pregnancy outcomes in pregnant women with normal thyroid function remains unclear.

Objective

This study aims to investigate the relationship between maternal TPOAb positivity and adverse pregnancy outcomes with normal thyroid function.

Methods

We collected baseline information from pregnant women who visited our hospital between February 2009 and June 2012. Blood samples were taken to measure thyroid stimulating hormone (TSH), free thyroxine (FT4), TPOAb, and anti-thyroglobulin antibodies (TGAb). The incidence of adverse pregnancy outcomes was compared between TPOAb-positive and TPOAb-negative groups among participants with normal thyroid function.

Results

A total of 7,046 pregnant women with normal thyroid function were included, comprising 6,700 with negative TPOAb and 346 with positive TPOAb. The TPOAb-positive group exhibited a higher age (26.0 vs. 27.0 years, p = 0.02) and greater serum TSH levels (1.72 vs. 1.94 mIU/L, p = 0.029), while the gestational week of blood collection was lower (31.9 vs. 26.5 weeks, p = 0.001). Univariate analysis revealed a higher incidence of low birth weight (LBW) in offspring of TPOAb-positive women compared to the TPOAb-negative group (3.5% vs. 1.9%, p = 0.035). After adjusting for confounding factors such as age, gestational week of blood collection, menstrual history, education level, gestational diabetes, gestational hypertension, TGAb, TSH, and FT4, TPOAb positivity emerged as an independent risk factor for LBW infants (OR: 2.317, 95% CI: 1.057-5.076, p = 0.036), while other adverse pregnancy outcomes did not show a significant correlation with TPOAb positivity.

Conclusion

Our findings suggest that TPOAb-positive pregnant women with normal thyroid function are more likely to deliver LBW infants. Regular monitoring of TPOAb-positive pregnancies and timely interventions throughout all stages of pregnancy are crucial.

Thyroid peroxidase antibody titers, thyroid function, and iodine nutrition status of pregnant normotensive and preeclamptic women in Eastern Cape South Africa

BACKGROUND

Autoimmune thyroid disease, one of the main risk factors for hypothyroidism, is associated with adverse pregnancy outcomes. The burden of autoimmune thyroid disease in pregnancy and its association with thyroid function among normotensive pregnant women and pregnant women with hypertension in South Africa are not known.

OBJECTIVE

This study aimed to establish the magnitude of thyroid peroxidase autoantibodies in pregnancy in the Eastern Cape of South Africa and its relationship with iodine nutrition status and preeclampsia.

STUDY DESIGN

Overall, 60 randomly selected normotensive pregnant controls at term and 120 pregnant participants with preeclampsia in the third trimester of pregnancy going to the Mthatha Regional Hospital and the Nelson Mandela Academic Hospital in the Eastern Cape Province who had complete data on thyroid peroxidase antibody titers, urinary iodine concentrations, serum thyroid-stimulating hormones, and free triiodothyronine, free thyroxine, and thyroglobulin levels were enrolled in this unmatched case-control study.

RESULTS

The cases and controls had similar mean chronological age (23.8 vs 24.0 years), body mass index (29.4 vs 28.8 kg/m2), and median parity (both 1) (P>.05). The controls had a higher mean gestational age than participants with preeclampsia (38.5 vs 33.7 weeks, respectively; P<.001). Both participants with preeclampsia and normotensive participants had median thyroid peroxidase antibody levels consistent with a negative thyroid autoimmune status. Participants with preeclampsia had higher but nonstatistically significant median thyroid peroxidase antibody (2.14 vs 1.77 IU/L), thyroglobulin (25.9 vs 21.3 µg/L), and thyroid-stimulating hormone (2.4 vs 2.3 mIU/L) levels (P>.05) and significantly lower median urinary iodine concentration (123.4 vs 188.6 µg/L), free thyroxine (13.2 vs 14.1 pmol/L), and free triiodothyronine (4.3 vs 4.6 pmol/L) levels (P<.05) than normotensive controls. Thyroid peroxidase antibodies were positively correlated with thyroglobulin, urinary iodine concentration, and thyroid-stimulating hormone.

CONCLUSION

In the rural Eastern Cape of South Africa, pregnant women in the third trimester of pregnancy have thyroid peroxidase antibody titers that show negative thyroid autoimmune status. Insufficient iodine intake, other than thyroid autoimmune disease, seems to be the underlying cause of the lower free triiodothyronine and free thyroxine levels observed among women with preeclampsia.

Effects of thyroid hormones in women with gestational diabetes

PURPOSE

This study aims to determine the effect of serum free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH) and fT3/fT4 ratio on the gestational diabetes.

METHODS

This multicenter study was conducted by analyzing retrospectively 495 pregnant women who admitted to the Tepecik training and Research Hospital, and Kocaeli Derince training and Research Hospital between January 2017 and December 2019. Seventy-eight pregnant women diagnosed with Gestational Diabetes Mellitus (GDM) and 82 pregnant women without GDM diagnosis were included in the study. The relationship between thyroid markers (TSH, fT3, fT4 and fT3/fT4) and gestational diabetes was determined using logistic regression analysis.

RESULTS

Advanced age, low fT4 and high TSH levels were higher in GDM group, p < .05. Results of the logistic regression analysis revealed that the gestational week (OR 20.291, 95% CI 3.132-131-449, p = .002], fasting plasma glucose (OR 48,551, 95% CI 9.223-255.582, p < .001), HbA1c (OR 13,671, 95%CI 2.977-62.781, p =.001) and fT3/fT4 (OR 29.934, 95% CI 3.558-251836, p = .002) were the risk factors of GDM.

DISCUSSION

Advanced gestational week, fasting blood glucose, HbA1c and fT3/fT4 ratio are among the risk factors for the development of the gestational diabetes.

Cord blood metabolomics reveals gestational metabolic disorder associated with anti-thyroid peroxidase antibodies positivity

Background

Thyroid disease is one of the common endocrine disorders affecting the pregnant women, in which thyroid autoimmunity can alter the progress and the outcome of pregnancy. Women with euthyroid status but anti-thyroid peroxidase (anti-TPO) antibodies positivity before pregnancy are prone to subclinical gestational hypothyroidism. However, the connections between anti-TPO antibodies positivity and gestational hypothyroidism remain largely unknown. The aim of the present study is to investigate the differences of fetal metabolic profile at birth according to maternal anti-TPO status.

Methods

We performed 1H-NMR metabolomics on cord blood of a nested case control cohort of 22 pregnant women with matched thyroid hormone levels and demographic data, including 11 women with euthyroid status but anti-thyroid antibodies positivity (into the anti-TPO antibodies positivity group) and 11 matched women as controls with euthyroid status and negative anti-thyroid antibodies (into the control group).

Results

Distinct metabolic profiles were observed between the anti-TPO antibody positivity group and the nested control group, from which a total of 10 metabolites with between-group altered abundances were structurally identified. Five out of the 10 metabolites were up-regulated in the anti-TPO antibodies positivity group, including D-Glucose, L-Glutamine, 3-Hydroxybutyric acid, Myo-Inositol, Creatinine. The other 5 metabolites were down-regulated in the anti-TPO antibodies positivity group, including L-Leucine, L-Lysine, L-Glutamic acid, L-Tyrosine, and L-Phenylalanine. All the 10 metabolites have been previously reported to be correlated with hypothyroidism. Metabolite set enrichment analysis and pathway analysis suggested that amino acid metabolism pathways (especially the phenylalanine metabolism) were associated with anti-TPO antibodies positivity.

Conclusion

The results of this study suggested that fetal metabolic disorder is correlated with anti-TPO antibodies positivity, representing by abundance alteration of hypothyroidism associated metabolites and the related disturbance of amino acid metabolism pathways.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04564-8.

Thyroid Function During Pregnancy in A Multiethnic Population in Norway

Context

Ethnic differences in thyroid function during pregnancy have been reported. However, it is unclear if this is equally valid across ethnic groups within multiethnic populations.

Objective

We aimed to assess ethnic differences in thyrotropin (TSH) and free thyroxine (FT4), and the prevalence of thyroid dysfunction and thyroid autoimmunity during pregnancy.

Methods

In a population-based cohort of 785 pregnant women in Oslo, Norway, TSH, FT4, and thyroid peroxidase antibodies (TPO Abs) were measured twice: at gestational week (GW) 15 and 28, and urine iodine concentration at GW 15. Associations were assessed using multivariate linear regression.

Results

We found ethnic differences in TSH levels at both time points, but not for fT4. South Asians had 0.42 mU/L (95% CI, 0.20-0.64) higher TSH than Europeans in GW 15. This difference persisted after adjusting for covariates (including TPO Ab positivity and iodine status), and increased further as pregnancy progressed. In contrast, East Asians had the lowest TSH. No new cases of overt hypothyroidism were detected in early pregnancy, but subclinical hypothyroidism was found in 6.6% among all, highest in South Asians (14.2%). Hyperthyroidism early in pregnancy was observed in 3.7% (almost all subclinical), highest in East Asians (11.9%). The prevalence of TPO Ab positivity was 4%, highest in South Asians (8%).

Conclusion

In a multiethnic population of presumably healthy women, we found ethnic variations in TSH but not FT4 levels throughout pregnancy. South Asians had higher TSH and more subclinical hypothyroidism, not explained by their higher prevalence of TPO Ab positivity. Larger studies are needed to define ethnic- and trimester-specific reference ranges in pregnancy.

Variations in the Antithyroid Antibody Titre During Pregnancy and After Delivery

Background

Immunosuppression occurs during pregnancy, and the antithyroid antibody titre drops, rebounding after delivery. We aimed to determine variations in antithyroid antibody titres during pregnancy and after delivery.

Methods

This retrospective study was conducted in a single centre. Antibody titres of 142 patients were measured to assess variations in the levels of thyroid-stimulating hormone receptor antibodies (TRAbs), thyroid peroxidase antibodies (TPOAbs), and thyroid globulin antibodies (TgAbs). We compared the titres of each antibody between adjacent time periods (eg, first trimester (T1) vs second trimester (T2), T2 vs third trimester (T3), T3 vs the postpartum period (PP)) by paired t-test or the Wilcoxon test. Then, we analysed data from patients with complete laboratory examination results in all four periods with the Friedman test, performing comparisons among groups.

Results

In the TgAb group, significant differences existed between T1 and T2 and between T2 and T3 in the LT4 subgroup and between T1 and T2 in the no-medication subgroup. In the TRAb group, significant differences existed between T1 and T2 in the LT4 subgroup. In the TPOAb group, significant differences existed among each group in the LT4 subgroup, and there were significant differences between T1 and T2 and between T2 and T3 in the no-medication subgroup. The Friedman test showed that the P-values were 0.013 and 0.004 in the LT4 and no-medication subgroups of the TgAb group, respectively; 0.122 in the LT4 subgroup of the TRAb group; and <0.001 and 0.272 in the LT4 and no-medication subgroups of the TPOAb group, respectively. In the LT4 subgroup of the TgAb group, the P-values for comparisons of time periods were 0.602 between T1 and T2, 0.602 between T2 and T3, 0.006 between T1 and T3, and 0.602 between T3 and PP. In the no-medication subgroup of the TgAb group, the P-values were 0.078 between T1 and T2, 1.000 between T2 and T3, 0.011 between T1 and T3, and 0.078 between T3 and PP. In the LT4 subgroup of the TPOAb group, the P-values were 0.09 between T1 and T2, 0.014 between T2 and T3, <0.001 between T1 and T3, and 0.772 between T3 and PP.

Conclusion

We can conclude that the TgAb and TPOAb titres dropped during pregnancy.

Isolated maternal hypothyroxinemia and adverse pregnancy outcomes: A systematic review

Maternal thyroid hormones are vital for a normal pregnancy and the development of fetus and childhood; inadequate availability of thyroid hormones during pregnancy is associated with adverse pregnancy outcomes. Isolated maternal hypothyroxinemia (IMH) is defined as a low maternal T4 in the absence of TSH elevation. This systematic review aimed to investigate the association between IMH and adverse pregnancy outcomes. PubMed, Scopus and Web of science were searched for retrieving observational studies published up to September 2020, investigating the association of IMH with adverse pregnancy outcomes. From a total of 308 articles, 17 met our eligibility criteria and were used for the purpose of the present study. Definition of IMH varied in different studies. While some studies reported no adverse pregnancy outcomes for IMH, other studies found a positive association between first trimester IMH and feto-maternal outcomes including gestational hypertension, gestational diabetes, preterm delivery, fetal distress, small for gestational age, musculoskeletal malformations, spontaneous abortion, placental abruption and macrosomia. IMH, identified in the second trimester was associated with an increase in the risk of gestational diabetes, and hypertensive disorders of pregnancy in one study. There is no consensus on the adverse effects of IMH on pregnancy outcomes. Further comprehensive cohort studies using one standard definition for IMH, with large sample size and control of important confounders such as iodine status and maternal Thyroid peroxidase antibody (TPOAb) are needed for precise assessment of this association.

The Clinical Value and Variation of Antithyroid Antibodies during Pregnancy

Antithyroid antibodies, which include thyroid-stimulating hormone receptor antibodies (TRAbs), thyroid peroxidase antibodies (TPOAbs), and thyroid globulin antibodies (TgAbs), are widely known for their tight association with thyroid autoimmune diseases. The variation in all three kinds of antibodies also showed different trends during and after pregnancy (Weetman, 2010). This article reviewed the the physiological changes, while focusing on the variation of thyroid antibodies concentration in women during and after pregnancy, and adverse consequences related to their elevation. Since abnormal elevations of these antithyroid antibodies may lead to adverse outcomes in both mothers and fetuses, special attention must be paid to the titer of the antibodies during pregnancy. The molecular mechanisms of the variations in those antibodies have yet to be explained. The frequency and timing of thyroid antibody measurement, as well as different reference levels, also remain to be elucidated.

The Need for Dynamic Clinical Guidelines: A Systematic Review of New Research Published After Release of the 2017 ATA Guidelines on Thyroid Disease During Pregnancy and the Postpartum

Background: The American Thyroid Association Guidelines on Thyroid Disease During Pregnancy and the Postpartum (ATA Guidelines) were published in 2017, with an update not expected for another 5 years. Since release of the 2017 ATA Guidelines, greater than 500 articles have been published in the field. Furthermore, there are presently 14 prospective, interventional trials in progress registered at Clinicaltrials.gov Static guidelines updated every 5-7 years fail to provide timely evidence-based guidance to practicing clinicians. Consequently, guideline development should move toward the creation of dynamic documents. The present article reviews the literature published since the 2017 ATA Guidelines, both to benefit clinicians in practice and to make the case for Dynamic ATA Guidelines. Methods: Using the search terms "thyroid" and "pregnancy," a systematic review of literature published in Pubmed from 3/1/2017 to 12/31/2018 was conducted. The titles and/or abstracts of all articles were reviewed. All articles were classified by subject headings used in the 2017 ATA Guidelines. English-text articles classified under "hypothyroidism" or "thyroid autoimmunity" were examined in full-text. Using the questions and recommendations put forth by the previous ATA Guidelines, relevant articles were selected for discussion in this review. Results: At the time of the search, 659 unique articles on "thyroid and pregnancy" were identified, including 66 original studies on hypothyroidism and 26 on thyroid autoimmunity. Of these, 26 studies on hypothyroidism and 18 studies on thyroid autoimmunity were selected for inclusion in this review based on specific questions in the 2017 ATA Guidelines. Based on these 44 articles, we propose two specific changes to the 2017 ATA Guidelines. Conclusion: Based on new research, we recommend the 2017 ATA Guidelines be updated to recommend against treating thyroid antibody-negative women diagnosed with subclinical hypothyroidism in the second trimester or later; to reflect new, moderate-quality evidence supporting the treatment of thyroid peroxidase antibody-negative women with elevated thyroid stimulating hormone levels in the first trimester or earlier; and to recommend against treatment of euthyroid, thyroid peroxidase antibody-positive women undergoing assisted reproductive technology. Transitioning to a Dynamic ATA Guidelines would allow for these and future recommendations to be implemented in real time.