Autoimmune thyroid disease in pregnancy and the postpartum period: relationship to spontaneous abortion

Evaluation of the Fetal Brain in Maternal Hypothyroidism and Thyroid Autoantibody Positivity: A Prospective Case-Control Study

Background/Objectives: Maternal thyroid function plays a crucial role in fetal brain development, yet the potential impact of maternal hypothyroidism and thyroid autoimmunity on fetal intracranial structures remains inadequately explored. To investigate the impact of maternal hypothyroidism and thyroid autoimmunity on fetal intracranial structures, focusing on potential alterations in critical brain parameters during mid-gestation. Methods: This prospective case-control study included pregnant women between 18 and 24 weeks of gestation. Participants were divided into three groups: hypothyroidism and antibodies (Ab) group, hypothyroidism and Ab(-) group, and the control group. Ultrasonographic measurements of fetal intracranial structures such as the posterior lateral ventricle (PLV), cavum septum pellucidi (CSP), cisterna magna (CM), thalamus, and transcerebellar diameter (TCD) were recorded and compared. Results: A total of 153 pregnant women were evaluated (n = 52 in the hypothyroidism and Ab(+) group, n = 51 in the hypothyroidism and Ab(-) group, and n = 50 in the control group). Although most of the biometric parameters were similar across the groups, the hypothyroidism and Ab(+) group exhibited significantly lower PLV and thalamus measurements compared to the control group (p < 0.05). Additionally, there was a notable difference in the BMI among the groups, with hypothyroid participants (with or without antibodies) showing higher rates of being overweight or obese. Conclusions: Maternal hypothyroidism and the presence of thyroid autoantibodies may be associated with subtle changes in fetal brain structures during the mid-gestation period, particularly in the thalamus and PLV.

Effect of anti-thyroid antibodies on recurrent miscarriage: A meta-analysis

SETTING

Previous studies addressed the association between anti-thyroid antibodies and recurrent miscarriage (RM), however, the role of anti-thyroid antibodies in RM patients is debatable.

OBJECTIVES

Therefore, we conducted this meta-analysis and the aim of this current study was to assess whether anti-thyroid peroxidase (anti-TPO) and/or anti-thyroglobulin (anti-TG) antibody positivity was associated with RM.

DESIGN

A meta-analysis was conducted.

PARTICIPANTS

Recurrent miscarriage patients.

METHODS

STATA 12.0 software were applied to compute odds ratios (ORs)/relative risks (RRs) and 95% CIs regarding association between anti-TPO and anti-TG antibodies and the prevalence of RM.

RESULTS

N = 28 studies (8875 participants) explored effect of anti-thyroid antibodies on RM. Analysis of the 28 studies revealed significant association between anti-TPO, anti-TG antibodies and the prevalence of RM with a random effects model (OR/RR = 2.02; 95% CI: 1.63-2.51, p < 0.001; I2 = 44.3%, p value for Q test = 0.004). Analysis of the 20 studies revealed significant association between anti-TPO antibodies and the prevalence of RM with a random effects model (OR/RR = 1.59; 95% CI: 1.25-2.03, p < 0.001; I2 = 43.1%, p value for Q test = 0.022). Analysis of the 14 studies revealed significant association between anti-TG antibodies and the prevalence of RM with a random effects model (OR/RR = 2.25; 95% CI: 1.56-3.23, p < 0.001; I2 = 49.2%, p value for Q test = 0.019).

CONCLUSIONS

Based on the currently available analysis, our findings suggest that women with anti-TPO and/or anti-TG antibodies have a higher risk of RM than that in negative antibody women. Further investigation is needed to better clarify the exact role of the anti-thyroid antibodies in RM and whether treatment is of benefit.

LIMITATIONS

First, differences from various detection methods and reagents used in different studies may affect the diagnostic interpretation of anti-thyroid antibodies, which might influence the accuracy of this meta-analysis. Second, positive anti-thyroid antibodies seem likely to be part of a more general disorder of maternal immune system, due to restrictions of funding and condition, a complete autoantibody screening investigation is hardly to conduct in all participants, and this could be a possible limitation of all included studies. Third, there is no mention of thyroxine therapy on RM, making the meta-analysis even more limited.

Thyroglobulin Antibodies in Women with Recurrent Pregnancy Loss: A Systematic Review and Meta-Analysis

Background: Thyroid autoimmunity is the most prevalent autoimmune disorder among women of reproductive age and has been suggested as a risk factor in recurrent pregnancy loss (RPL)-a condition in which couples suffer several consecutive pregnancy losses, but where a cause can be identified in less than half of the cases. Most studies have focused on thyroid peroxidase antibodies (TPOAbs), not considering the presence of thyroglobulin antibodies (TgAbs). The aim of this study was to systematically assess the prevalence of TgAb positivity in women with RPL, and whether TgAb positivity was associated with the outcome of the next pregnancy. Methods: A systematic literature search of PubMed and Embase (from inception to April 29, 2023) was performed for studies reporting on TgAbs in women with RPL. The primary outcome was TgAb positivity in women with RPL compared with women without RPL, with a secondary outcome of association between TgAb positivity and the outcome of the next pregnancy. Pooled effect estimates were expressed as odds ratios (ORs) with confidence intervals [CI] using a random-effects model. The study was registered with PROSPERO (No. CRD42022310232) and adhered to the PRISMA guidelines. Results: A total of 770 studies were screened, 28 of which could be included reporting data from a total of 6868 women. The prevalence of TgAb positivity in women with RPL ranged from 3.6% to 28% compared with 2.4% to 29% in women without RPL. The OR for TgAb positivity was 1.93 ([CI 1.27-2.92]; I2 = 63%) compared with women without RPL, and for TgAbs and/or TPOAbs 2.66 ([CI 1.75-4.05]; I2 = 69%). Four studies reported on the outcome of the next pregnancy after antibody measurement with highly heterogeneous results (OR for pregnancy loss ranging from 0.99 in one study to 10.0 in the other study, and two studies reported no data eligible for meta-analysis). Consequently, a meta-analysis could not be performed. Conclusions: Women with RPL were significantly more often TgAb-positive than women without RPL. Although there was a lack of studies reporting prospective outcomes, the findings of this study support the significance of awareness about the strong association between RPL and thyroid autoimmunity.

Thyroid Function Rather Than Thyroid Antibodies Affects Pregnancy and Perinatal Outcomes: Results of a Prospective Study

CONTEXT

Thyroid autoantibody positivity has been associated with an increased rate of obstetrical complications.

OBJECTIVE

We aimed to evaluate the role of thyroid autoantibodies in adverse pregnancy outcomes.

METHODS

This prospective study was conducted in the Endocrinology Unit of Pisa Hospital. A total of 975 pregnant women were studied from 2012 to 2021; 572 (59%) were diagnosed with autoimmune thyroid (AT) diseases; 403 (41%) served as controls. Levothyroxine (LT4) treatment was introduced when TSH was > 2.5 mIU/L in the AT group and when TSH was > 4 mIU/L in the controls. Rates of obstetrical complications in each group were measured.

RESULTS

Although the frequency of miscarriage in the AT group was greater (4.8%) than in the controls (2.9%), no significant differences were detected (P = 0.181). There were no differences between the 2 groups concerning the other pregnancy complications, and no association with the titer of thyroid antibodies was observed. The frequency of congenital malformations was greater in the AT group than in the controls (P = 0.019), but no correlation with major congenital malformations was detected (P = 0.872). Given that thyroid hormone concentrations were strictly controlled in our population, we documented a tendency (not significant) toward an increase in miscarriage and preterm birth among women with TSH > 4 mIU/L.

CONCLUSION

If thyroid function is adequately controlled, the presence and titer of thyroid autoantibodies does not negatively influence gestation. Although not significant, suboptimal thyroid hormone status seems to affect pregnancy outcomes more than thyroid autoimmunity.

A Predictive Role of Autoantibodies Against the Epitope aa168–183 of ENO1 in the Occurrence of Miscarriage Related to Thyroid Autoimmunity

Objective

The aim of the research is to study the association between the serum levels of autoantibodies against one important epitope (¹⁶⁸FMILPVGAANFREAMR¹⁸³, designated as P6) of α-enolase (ENO1-P6Abs) and miscarriage among euthyroid females with thyroid autoimmunity (TAI).

Methods

Anti-ENO1-P6 total IgG was investigated in 432 euthyroid women, and its four subclasses were analyzed in 184 euthyroid women. The serum FT4, TSH, TgAb, and TPOAb levels were determined using an electrochemiluminescence immunoassay. The serum ENO1-P6Ab and anti-protein disulfide isomerase A3 autoantibody (PDIA3Ab) levels were determined using an enzyme-linked immunosorbent assay.

Results

The serum levels of anti-ENO1-P6 total IgG, IgG2, IgG3, and IgG4 were significantly higher in euthyroid TAI females than in non-TAI controls. Additionally, anti-ENO1-P6 total IgG and its 4 subtypes were all markedly higher in euthyroid TAI females with pregnancy loss than those without miscarriage. Moreover, logistic regression analysis showed that highly expressed anti-ENO1-P6 total IgG, IgG1, IgG2, and IgG3 subtypes in the serum were all independent risk factors for euthyroid TAI-related miscarriage, and its IgG1 was also for non-TAI-related abortion. According to the trend test, the prevalence of miscarriage was increased in a titer-dependent manner with the raised levels of serum anti-ENO1-P6 total IgG and IgG1, IgG2, and IgG3 subtypes among euthyroid TAI females. The receiver operating characteristic curve analysis of anti-ENO1-P6 total IgG and IgG1, IgG2, and IgG3 subclass expressions in the serum for miscarriage prediction in euthyroid TAI females exhibited that the total areas under the curves were 0.773 ± 0.041, 0.761 ± 0.053, 0.827 ± 0.043, and 0.760 ± 0.050, respectively (all P <0.0001). Their corresponding optimal cut-off OD450 values were 0.68 (total IgG), 0.26 (IgG1), 0.97 (IgG2), and 0.48 (IgG3), with sensitivities of 70.8, 87.5, 83.3, and 85.4%, and specificities of 70.8, 59.1, 77.3, and 56.8%, respectively. There was an additive interaction between serum anti-ENO1-P6 and anti-PDIA3 total IgGs on the development of miscarriage (RERI = 23.6, AP = 0.79, SI = 5.37).

Conclusion

The highly expressed ENO1-P6Abs may be important risk factors for euthyroid TAI-related miscarriage. The serum levels of ENO1-P6Abs may become good predictive markers for pregnancy loss in euthyroid TAI females, especially its IgG2 subclass expression.

The expression of anti-protein disulfide isomerase A3 autoantibody is associated with the increased risk of miscarriage in euthyroid women with thyroid autoimmunity

Miscarriage frequently occurs in euthyroid women with thyroid autoimmunity (TAI), but its mechanisms remain unclear. Our previous study has found that the serum level of anti-protein disulfide isomerase A3 autoantibody (PDIA3Ab) was significantly increased in mice with TAI. This study was aimed to explore whether there could be an association between the expression of PDIA3Ab and the occurrence of miscarriage in euthyroid TAI women. It was found that the serum level of PDIA3Ab was significantly increased in euthyroid TAI women as compared with that of non-TAI controls. Especially, serum PDIA3Ab level was markedly higher in euthyroid TAI women with miscarriage than the ones without miscarriage. Furthermore, binary logistic regression analysis showed that the serum PDIA3Ab level was an independent risk factor for spontaneous abortion in euthyroid TAI women with an odds ratio of 13.457 (95% CI, 2.965-61.078). The receiver operating characteristic (ROC) analysis of serum PDIA3Ab expression for predicting the miscarriage in euthyroid TAI women showed that the area under the curve was 0.707 ± 0.05 (P < 0.001). The optimal cut-off OD450 value of serum PDIA3Ab was 0.7129 with a sensitivity of 52.5% and specificity of 86.3% in euthyroid TAI women. Trend test showed that the prevalence of spontaneous abortion was markedly increased with the rise of serum PDIA3Ab level among TAI women in a titer-dependent manner. In conclusion, serum PDIA3Ab expression may imply an increased risk of spontaneous abortion in euthyroid TAI women, and it can be used as a new predictive bio-marker.

The benefits of higher LMR for early threatened abortion: A retrospective cohort study

Problem

To investigate the relation of inflammation-related parameters and pregnancy outcome in women with the early threatened abortion.

Method of study

630 women with early threatened abortion were divided into two groups based on the pregnancy outcome. All of them had the blood routine examination before treating. The differences between two groups were analyzed by the Chi-squared test, Student T test, Mann-Whitney U test, Binary Logistic Regression, Marginal Structural Model and Threshold effect analysis.

Results

We found that there is no significant difference in the pregnancy outcome for NLR (OR:0.92, CI95%:0.72, 1.17) and PLR (OR:1.00, CI%:0.99, 1.01). However, a difference had a statistical significance in the pregnancy outcome when LMR less than 2.19 (OR:0.39, CI95%:0.19,0.82).

Conclusions

This study suggested that higher LMR was related to the lower risk of miscarriage in the women with early threatened abortion in a way.

Effect of antithyroid antibodies on women with recurrent miscarriage: A meta-analysis

Problem

The effect of thyroid autoimmunity (TAI) on the prevalence of recurrent miscarriage (RM) is highly debatable. No meta‐analysis has been published in the past decade to investigate the impact of TAI on women with RM.

Method of Study

Systemic literature search was conducted on PubMed, Embase, Cochrane, and Web of Science databases. English language literatures published between 1993 and 2019 were selected. We assessed the relationship between the prevalence of RM and thyroid peroxidase antibodies (TPO‐Ab) or antithyroid antibodies (ATA) and evaluated the thyroid‐stimulating hormone (TSH) level in TPO‐Ab‐positive women with RM. We also observed the treatment effect with levothyroxine (LT4) for RM. Review Manager 5.3 software was used to obtain the pooled odds ratios (OR).

Results

Analysis of 22 eligible studies revealed significant association between TPO‐Ab and the prevalence of RM (OR = 1.85; 95% CI, 1.38 to 2.49; P < .001)(n ≥ 3), (OR = 1.82; 95% CI, 1.13 to 2.92; P = .01) (n ≥ 3). Women with ATA + had higher risk of RM (OR = 2.36; 95% CI, 1.71 to 3.25; P < .00001)(n ≥ 3), (OR = 2.34; 95% CI, 1.70 to 3.22; P < .00001)(n ≥ 2). RM women with TPO‐Ab had higher TSH level when compared with those negative for TPO‐Ab (random‐effect SMD = 0.60; 95% CI, 0.31 to 0.90; P < .0001). We also found beneficial effects of LT4 supplementation on the outcome of live birth rate (LBR) among pregnant women with TPO‐Ab (OR = 3.04; 95% CI, 0.69 to 13.36; P = .14).

Conclusion

The presence of serum antithyroid antibodies does harms to women and can even lead to recurrent miscarriage; LT4 treatment may have beneficial to RM women.

The exploration of Hashimoto's Thyroiditis related miscarriage for better treatment modalities

Hashimoto's thyroiditis (HT) is the most prevalent autoimmune thyroid disease (ATD) worldwide and is strongly associated with miscarriage and even recurrent miscarriage (RM). Moreover, with a deepening understanding, emerging evidence has shown that immune dysfunctions caused by HT conditions, including imbalanced subsets of CD4+ T-helper cells, B regulatory (Breg) cells, high expression levels of CD56dim natural killer (NK) cells, and cytokines, possibly play an important role in impairing maternal tolerance to the fetus. In recent years, unprecedented progress has been made in recognizing the specific changes in immune cells and molecules in patients with HT, which will be helpful in exploring the mechanism of HT-related miscarriage. Based on these findings, research investigating some potentially more effective treatments, such as selenium (Se), vitamin D3, and intravenous immunoglobulin (IVIG), has been well developed over the past few years. In this review, we highlight some of the latest advances in the possible immunological pathogenesis of HT-related miscarriage and focus on the efficacies of treatments that have been widely introduced to clinical trials or practice described in the most recent literature.

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

OBJECTIVE

To study the prevalence of thyroid peroxidase autoantibody in euthyroid pregnant women and to evaluate the association between thyroid peroxidase autoantibody and pregnancy outcomes.

MATERIALS AND METHODS

One thousand thirty consecutive pregnant women attending the antenatal clinic over a period of 1 year and were carrying a healthy singleton uncomplicated intrauterine pregnancy and consuming iodized salt were recruited for the study. Outcomes of the pregnancy was compared between TPO antibody positive euthyroid women (group 1) and TPO antibody negative euthyroid women (group 2).

RESULTS

Out of 1030 women, 164 (18.9%) were detected TPO antibody positive with euthyroid status. The mean FT4 and TSH level were significantly different in those who were TPO Ab positive as compared TPO Ab negative euthyroid pregnant women. No correlation was observed between the maternal age, gestational age and gravidity with anti TPO antibody levels. Eighteen (12%) women in Group 1and 5 (3.3%) women in Group 2 had miscarriages and the difference was found to be statistically significant (P value of 0.004). Twenty-one (14%) women in Group 1 and 5 (3.3%) women in Group 2 had preterm deliveries, which was also found to be statistically significantly (p value of 0.001). Other pregnancy related complications like Intrauterine death, IUGR, preeclampsia and PIH though are present in comparatively higher number in TPO Ab positive euthyroid pregnant women as compared to TPO Ab negative euthyroid pregnant women but this difference was not found to be statistically significant.

CONCLUSIONS

To conclude with the present study shows that a good number of pregnant women with euthyroid status have TPO Ab positivity and this is associated with some adverse pregnancy outcomes like miscarriage and preterm birth of the baby.

Effects of levothyroxine treatment on pregnancy outcomes in pregnant women with autoimmune thyroid disease

BACKGROUND

Despite some studies indicating that thyroid antibody positivity during pregnancy has been associated with adverse pregnancy outcomes, evidence regarding the effects of levothyroxine (LT4) treatment of euthyroid/subclinical hypothyroid pregnant women with autoimmune thyroid disease on pregnancy outcome is limited. We aimed to assess whether pregnant women with autoimmune thyroid disease, but without overt thyroid dysfunction are affected by higher rates of adverse pregnancy outcomes. In addition, we aimed to explore whether LT4 treatment improves the pregnancy outcome of affected women.

METHODS

A prospective study was carried out on pregnant women from the first trimester to delivery. The study was conducted among pregnant women receiving prenatal care in centers under coverage of Shahid Beheshti University of Medical Sciences. Of a total of 1746 pregnant women, screened for thyroid dysfunction, 1028 euthyroid TPOAb-negative (TPOAb^-) and 131 thyroid peroxidase antibody-positive (TPOAb⁺) women without overt thyroid dysfunction entered the second phase of the study. TPOAb⁺ women were randomly divided into two groups: group A (n = 65), treated with LT4 and group B (n = 66), received no treatment. The 1028 TPOAb^- women (group C) served as a normal population control group. Primary outcomes were preterm delivery and miscarriage and secondary outcomes included placenta abruption, still birth, neonatal admission and neonatal TSH levels.

RESULTS

Groups A and C displayed a lower rate of preterm deliveries compared with group B (RR = 0.30, 95% CI: 0.1-0.85, P = 0.0229) and (RR = 0.23, 95% CI: 0.14-0.40, P < 0.001) respectively. There was no statistically significant difference in the rates of preterm labor between groups A and C (RR = 0.79, 95% CI: 0.30-2.09, P = 0.64). The number needed to treat (NNT) for preterm birth was 5.9 (95% CI: 3.33–25.16).

CONCLUSIONS

Treatment with LT4 decreases the risk of preterm delivery in women who are positive for TPOAb.

Thyroid autoantibodies and the effect on pregnancy outcomes

Thyroid antibody positivity is relatively common in women. While many epidemiological studies have investigated the links between thyroid antibodies and pregnancy complications, evidence regarding the effect of Levothyroxine treatment of euthyroid pregnant women with autoimmune thyroid disease on pregnancy outcome is limited. The objective of this paper is to provide a review on the impact of treatment of euthyroid thyroid antibody-positive pregnant women on adverse pregnancy outcome. This systematic review was conducted with a prospective protocol. PubMed, Science direct, Google scholar, Embase and the Cochrane Library databases were searched through January 2014 to identify studies that met pre-stated inclusion criteria. The search was limited to English manuscripts. We found that there is inadequate data regarding both the adverse effect of thyroid antibody positivity in euthyroid women on pregnancy outcomes and the effects Levothyroxine on these women. It seems that the results of most studies indicate adverse effects of thyroid antibody positivity in euthyroid women on pregnancy outcomes. Further randomised clinical trials are needed to investigate the effects of treating pregnant euthyroid women with positive thyroid antibodies on the maternal and early/late neonatal outcomes.

Thyroid in pregnancy: From physiology to screening

Thyroid hormones are crucial for the growth and maturation of many target tissues, especially the brain and skeleton. During critical periods in the first trimester of pregnancy, maternal thyroxine is essential for fetal development as it supplies thyroid hormone-dependent tissues. The ontogeny of mature thyroid function involves organogenesis, and maturation of the hypothalamus, pituitary and the thyroid gland; and it is almost complete by the 12th-14th gestational week. In case of maternal hypothyroidism, substitution with levothyroxine must be started in early pregnancy. After the 14th gestational week, fetal brain development may already be irreversibly affected by lack of thyroid hormones. The prevalence of manifest hypothyroidism in pregnancy is about 0.3-0.5%. The prevalence of subclinical hypothyroidism varies between 4 and 17%, strongly depending on the definition of the upper TSH cutoff limit. Hyperthyroidism occurs in 0.1-1% of all pregnancies. Positivity for antibodies against thyroid peroxidase (TPOAb) is common in women of childbearing age with an incidence rate of 5.1-12.4%. TPOAb-positivity may be regarded as a manifestation of a general autoimmune state which may alter the fertilization and implantation processes or cause early missed abortions. Women positive for TPOAb are at a significant risk of developing hypothyroidism during pregnancy and postpartum. Laboratory diagnosis of thyroid dysfunction during pregnancy is based upon serum TSH concentration. TSH in pregnancy is physiologically lower than the non-pregnant population. Results of multiple international studies point toward creation of trimester-specific reference intervals for TSH in pregnancy. Screening for hypothyroidism in pregnancy is controversial and its implementation varies from country to country. Currently, the case-finding approach of screening high-risk women is preferred in most countries to universal screening. However, numerous studies have shown that one-third to one-half of women with thyroid disorders escape the case-finding approach. Moreover, the universal screening has been shown to be more cost-effective. Screening for thyroid disorders in pregnancy should include assessment of both TSH and TPOAb, regardless of the screening approach. This review summarizes the current knowledge on physiology of thyroid hormones in pregnancy, causes of maternal thyroid dysfunction and its effects on pregnancy course and fetal development. We discuss the question of case-finding versus universal screening strategies and we display an overview of the analytical methods and their reference intervals in the assessment of thyroid function and thyroid autoimmunity in pregnancy. Finally, we present our results supporting the implementation of universal screening.

The Effect of Anti-Thyroid Peroxidase Antibodies on Pregnancy Outcomes in Euthyroid Women

INTRODUCTION

Thyroid autoimmunity can have an adverse impact on the outcome of the pregnancy. Although the adverse effects of antithyroid antibodies have been well studied in hypothyroid women, their effects in euthyroid women are not well evaluated.

AIM

The study was conducted to assess the overall prevalence of anti-Thyroid Peroxidase (anti-TPO) antibodies in pregnant women and the effect of anti-TPO positivity on the outcome of pregnancy in euthyroid women.

MATERIALS AND METHODS

One thousand Indian women, in their first trimester were screened for anti-TPO antibodies to know the prevalence. Of this, euthyroid women who were positive for the presence of anti-TPO antibody were selected and their obstetric history was recorded. These women were followed up and the incidences of maternal and foetal complications were recorded. The complications were compared with the past obstetric history and outcomes in parity and gestation matched controls (anti-TPO negative).

RESULTS

The prevalence of anti-TPO positivity was 11% (n=110). Out of the positives, those with elevated Thyroid Stimulating Hormone (TSH) were 6.5%. The prevalence of euthyroid women who were anti-TPO positive was 4% (n=40). Anti-TPO positive, euthyroid females had a higher prevalence of infertility, anaemia and preterm delivery as compared to the controls (p<0.0001). No differences were observed between the two groups in terms of history of abruption recurrent abortions, intrauterine growth restriction, postpartum haemorrhage, symptomatic hypothyroidism, hypertensive disorders of pregnancy and foetal complications.

CONCLUSION

Anti-TPO positivity is common in pregnant women. Anti-TPO positive euthyroid females had a higher prevalence of infertility, anaemia as well as preterm delivery. Our results indicate that anti-TPO screening in pregnancy, may aid in early identification of the women at risk.

Pregnancy Outcome in Euthyroid Women with Anti-Thyroid Peroxidase Antibodies

OBJECTIVE

The aim of this study was to compare pregnancy outcomes in euthyroid women who were anti-TPO Ab(+) with those who were anti-TPO Ab(-).

DESIGN

This observational study comprised 1,000 women in the age group of 25-35 years, having normal thyroid function tests, normotensive, non-diabetic, singleton pregnancy and attending Gyn. OPD/ANC up to 20 weeks' gestation and those who were already in the process of abortion. anti-TPO Ab levels of >50 IU/ml were considered as anti-TPO Ab(+).

SETTING

This study was conducted in the SMS Medical College's attached hospital, Jaipur from April 2012 to September 2013.

MAIN OUTCOME

The estimation of the proportion of anti-TPO Abs in the hospital-based population and the comparison of pregnancy and neonatal outcomes in anti-TPO Ab(+) and Ab(-) euthyroid women were done.

RESULTS

The main result showed increased rates in miscarriages (13.33 vs. 2.34 %, P < 0.001), LBWs (25 vs. 5.12 %, P < 0.001), preterm deliveries [<34 weeks] (5 vs. 1.80 %, P > 0.05) in anti-TPO Ab(+) women.

CONCLUSIONS

The current study revealed that anti-TPO Abs are strongly associated with miscarriage and LBW irrespective of their gestational age. However, we did not find any correlation with the other complication as found in the studies by Abbassi-Ghanavati, Negro et al.

Thyroid autoimmunity in pregnant Nigerians

CONTEXT

Thyroid autoimmunity is a recognized disorder in pregnancy and is associated with a number of adverse pregnancy outcomes.

AIM

This study set out to determine the relationship between pregnancy and thyroid autoimmunity in Nigerian women.

SETTINGS AND DESIGN

This was an analytical cross-sectional study carried out in a tertiary hospital in South Western Nigeria with a total study population of 108 pregnant and 52 nonpregnant women.

SUBJECTS AND METHODS

Serum thyroid stimulating hormone, free thyroxine and thyroid peroxidase antibodies (TPO-Ab) were quantitatively determined using enzyme linked immuno-assays. Pregnant women were grouped into three categories (<14 weeks, 14-28 weeks and > 28 weeks). The relationship between pregnancy and thyroid autoimmunity was determined using Spearman correlation. Analysis of variance was used in comparison of means, Chi-square test used in analyzing proportions while P ≤ 0.05 was considered as significant.

RESULTS

The mean age of the pregnant women was 30.4 ± 6.0 years while the mean gestational age of all pregnant women was 20.6 ± 9.6 weeks. The mean TPO-Ab of 11.58 IU/ml in the pregnant was significantly higher than that of the controls of 7.23 IU/ml (P < 0.001). Out of 108 pregnant women, 27 (25%) had elevated TPO-Ab as against about 2% of the nonpregnant women levels P < 0.001. The number of pregnant women with elevated TPO-Ab levels decreased from 33.3% in the first group to 25.6% and 15.2% in the second and third groups.

CONCLUSION

Thyroid autoimmunity expressed by the presence of TPO-Ab is high among pregnant Nigerian women and the frequency of autoimmunity appears to decline with advancing gestational age.

Clinical practice guidelines for the management of hypothyroidism

INTRODUCTION

Hypothyroidism has long been known for its effects on different organ systems, leading to hypometabolism. However, subclinical hypothyroidism, its most prevalent form, has been recently related to cardiovascular risk and also to maternal-fetal complications in pregnant women.

OBJECTIVES

In these clinical practice guidelines, several aspects of this field have been discussed with the clear objectives of helping physicians treat patients with hypothyroidism, and of sharing some of our Latin American-based clinical experience.

MATERIALS AND METHODS

The Latin American Thyroid Society commissioned a Task Force on Hypothyroidism to develop evidence-based clinical guidelines on hypothyroidism. A systematic review of the available literature, focused on the primary databases of MedLine/PubMed and Lilacs/SciELO was performed. Filters to assess methodological quality were applied to select the best quality studies. The strength of recommendation on a scale from A-D was based on the Oxford Centre for Evidence--based Medicine, Levels of Evidence 2009, allowing an unbiased opinion devoid of subjective viewpoints. The areas of interest for the studies comprised diagnosis, screening, treatment and a special section for hypothyroidism in pregnancy.

RESULTS

Several questions based on diagnosis, screening, treatment of hypothyroidism in adult population and specifically in pregnant women were posed. Twenty six recommendations were created based on the answers to these questions. Despite the fact that evidence in some areas of hypothyroidism, such as therapy, is lacking, out of 279 references, 73% were Grade A and B, 8% Grade C and 19% Grade D.

CONCLUSIONS

These evidence-based clinical guidelines on hypothyroidism will provide unified criteria for management of hypothyroidism throughout Latin America. Although most of the studies referred to are from all over the world, the point of view of thyroidologists from Latin America is also given.

Thyroid autoimmunity and obstetric outcomes in women with recurrent miscarriage: a case-control study

OBJECTIVES

Thyroid antibody positivity during pregnancy has been associated with adverse outcomes including miscarriage and preterm delivery. The aim of the study is to evaluate the obstetric outcome in pregnant women with recurrent miscarriage and their response to levothyroxine (l-T4) therapy.

STUDY DESIGN AND METHODS

All pregnant and non-pregnant women between 21 and 35 years of age with a history of two or more consecutive miscarriages were included in the study. A third group comprising 100 pregnant women without a history of miscarriage were taken as healthy controls. Thyroid autoimmunity, prevalence of subclinical hypothyroidism and maternal and foetal complications were analysed in all the groups with appropriate statistical methods.

RESULTS

The mean age of the patients included in the study was 27.0±3.1 years. Of 100 pregnant patients with previous recurrent miscarriage, thyroid autoimmunity (thyroid peroxidase antibody (TPOAb(+)) >34 U/ml) was found in 31% of the cases. The incidence of subclinical hypothyroidism was higher in TPOAb(+) group than in TPOAb(-) group (52 vs 16%; P=0.0002). There was no difference in the prevalence of miscarriage or obstetric outcomes between recurrent miscarriage and healthy pregnant women group irrespective of TPO status.

CONCLUSIONS

The prevalence of thyroid autoimmunity was higher in pregnant women with a history of recurrent abortion compared with healthy pregnant control population. Following l-T4 treatment, there was no difference in prevalence of miscarriage between hypothyroid and euthyroid individuals in TPOAb(+) women.

Screening for maternal thyroid dysfunction in pregnancy: a review of the clinical evidence and current guidelines

Observational studies have demonstrated that maternal thyroid dysfunction and thyroid autoimmunity in pregnancy may be associated with adverse obstetric and fetal outcomes. Treatment of overt maternal hyperthyroidism and overt hypothyroidism clearly improves outcomes. To date there is limited evidence that levothyroxine treatment of pregnant women with subclinical hypothyroidism, isolated hypothyroxinemia, or thyroid autoimmunity is beneficial. Therefore, there is ongoing debate regarding the need for universal screening for thyroid dysfunction during pregnancy. Current guidelines differ; some recommend an aggressive case-finding approach, whereas others advocate testing only symptomatic women or those with a personal history of thyroid disease or other associated medical conditions.

Infertility and pregnancy loss in euthyroid women with thyroid autoimmunity

Thyroid autoimmunity is the most prevalent autoimmune state that affects up to 5-20% of women during the age of fertility. Prevalence of thyroid autoimmunity is significantly higher among infertile women, especially when the cause of infertility is endometriosis or polycystic ovary syndrome. Presence of thyroid autoimmunity does not interfere with normal embryo implantation and have been observed comparable pregnancy rates after assisted reproduction techniques in patients with or without thyroid autoimmunity. Instead, the risk of early miscarriage is substantially raised with the presence of thyroid autoimmunity, even if there was a condition of euthyroidism before pregnancy. Furthermore the controlled ovarian hyperstimulation, used as preparation for assisted reproduction techniques, can severely impair thyroid function increasing circulating estrogen levels. Systematic screening for thyroid disorders in women with a female cause of infertility is controversial but might be important to detect thyroid autoimmunity before to use assisted reproduction techniques and to follow-up these parameters in these patients after controlled ovarian hyperstimulation and during pregnancy.

Reduction of miscarriages through universal screening and treatment of thyroid autoimmune diseases

BACKGROUND/AIMS

Universal screening for thyroid diseases during pregnancy is controversial. Targeted screening does not identify all women with thyroid dysfunction. Furthermore, antithyroid peroxidase antibodies (TPOAb) are suspected to be associated with an increased risk of fetal loss, premature delivery and hypothyroidism. The aim of our study was to assess the rationale behind universal screening and propose thyroxine treatment in particular cases.

METHODS

Between January 2008 and May 2009, 537 consecutive iodine-supplemented women with a singleton pregnancy [441 TPOAb- controls and 96 TPOAb+ women (47 nontreated and 49 treated)] were evaluated using thyroid and obstetric parameters. According to our algorithm for thyroid screening in pregnancy, if thyroid-stimulating hormone (TSH) exceeded 1 mU/l in TPOAb+ women, 50 µg of levothyroxine (L-T4) was prescribed.

RESULTS

The miscarriage rate was significantly higher in the nontreated TPOAb+ group compared with the treated group (16 vs. 0%; p = 0.02). Compared to the control group, TSH in TPOAb+ patients was higher at the first prenatal visit prior to L-T4 treatment (p < 0.01), while free thyroxine was higher than in the control group after the 20th week (p < 0.05).

CONCLUSIONS

Our study supports the potential benefit of universal screening and L-T4 treatment for autoimmune thyroid disease during pregnancy. Efforts are still needed to further decrease miscarriage rates.

Thyroid dysfunction and autoantibodies association with hypertensive disorders during pregnancy

Background. Thyroid dysfunction and autoimmunity are relatively common in reproductive age and have been associated with adverse health outcomes for both mother and child, including hypertensive disorders during pregnancy. Objective. To survey the relation between thyroid dysfunction and autoimmunity and incidence and severity of pregnancy-induced hypertensive disorders. Method. In this case control study 48 hypertensive patients in 4 subgroups (gestational hypertension, mild preeclampsia, severe preeclampsia, eclampsia) and 50 normotensive ones were studied. The samples were nulliparous and matched based on age and gestational age and none of them had previous history of hypertensive or thyroid disorders and other underlying systemic diseases or took medication that might affect thyroid function. Their venous blood samples were collected using electrochemiluminescence and ELISA method and thyroid hormones and TSH and autoantibodies were measured. Results. Hypertensive patients had significant lower T3 concentration compared with normotensive ones with mean T3 values 152.5 ± 48.93 ng/dL, 175.36 ± 58.07 ng/dL respectively. Anti-TPO concentration is higher in control group 6.07 ± 9.02 IU/mL compared with 2.27 ± 2.94 IU/mL in cases. Conclusion. The severity of preeclampsia and eclampsia was not associated with thyroid function tests. The only significant value was low T3 level among pregnancy, induced hypertensive patients.

Thyroid function in pregnancy

Iodine is required for the production of thyroid hormones. Normal thyroid function during pregnancy is important for both the mother and developing fetus. This review discusses the changes in thyroid physiology that occur during pregnancy, the significance of thyroid function tests and thyroid antibody titers assessed during pregnancy, and the potential obstetric complications associated with maternal hypothyroidism.

Thyroid autoantibodies and pregnancy outcomes

Autoimmune thyroid disease has been associated with several adverse pregnancy outcomes. Increased risk of spontaneous miscarriage and placental abruption in women with thyroid antibodies has been confirmed in multiple studies. However, benefit of intervention and treatment of autoimmune thyroid disease in otherwise euthyroid pregnant women has not been sufficiently studied. The data on the association of thyroid antibodies and recurrent pregnancy loss or preterm birth are conflicting and a statistically significant association has not been shown in large studies. At present time, routine screening and treatment of autoimmune thyroid disease in euthyroid pregnant women is not warranted.

Thyroid autoimmunity and recurrent miscarriage

PROBLEM

To investigate the role of antithyroid autoantibodies (ATA) in recurrent miscarriage (RM).

METHODS

In this case-control study, a total of 160 women with RM and 100 healthy women were investigated for the presence of serum ATA directed against thyreoglobulin (TG-Ab), thyroid peroxidase (TPO-Ab) and TSH receptor (TSHr-Ab), which were determined by either chemiluminescence or radioimmunoassay.

RESULTS

Antithyroid autoantibodies were detected in 46 (28.75%) women with RM and in 13 (13%) women of the control group (P < 0.05). The frequencies for TG-Ab and TPO-Ab were higher in RM than in control women. Among the women of RM group, 91.3% of ATA+ women were positive also for other autoantibodies. The majority of study women were euthyroid.

CONCLUSIONS

Antithyroid autoantibodies, particularly TG-Ab, are associated with RM and could be an expression of a more general maternal immune system abnormality leading to RM. ATA could have a role in RM irrespective of thyroid hormone status.

Thyroid antibodies and miscarriage: where are we at a generation later?

In 1990, an association between thyroid antibody positivity and spontaneous miscarriage was first reported. A generation has passed since the initial observation. Over that time a robust literature has developed which has confirmed the initial finding and expanded upon it. The present paper reviews the literature that has been generated over the last twenty years on the following topics: (1) thyroid antibodies and spontaneous miscarriage, (2) thyroid antibodies and recurrent abortion, (3) etiology of pregnancy loss in thyroid antibody positive women, and (4) discussion of future research directions.

Association between thyroid autoantibodies and miscarriage and preterm birth: meta-analysis of evidence

OBJECTIVES

To evaluate the association between thyroid autoantibodies and miscarriage and preterm birth in women with normal thyroid function. To assess the effect of treatment with levothyroxine on pregnancy outcomes in this group of women.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, Cochrane Library, and SCISEARCH (inception-2011) without any language restrictions. We used a combination of key words to generate two subsets of citations, one indexing thyroid autoantibodies and the other indexing the outcomes of miscarriage and preterm birth.

STUDY SELECTION

Studies that evaluated the association between thyroid autoantibodies and pregnancy outcomes were selected in a two stage process. Two reviewers selected studies that met the predefined and explicit criteria regarding population, tests, and outcomes.

DATA SYNTHESIS

Odds ratios from individual studies were pooled separately for cohort and case-control studies with the random effects model.

RESULTS

30 articles with 31 studies (19 cohort and 12 case-control) involving 12,126 women assessed the association between thyroid autoantibodies and miscarriage. Five studies with 12,566 women evaluated the association with preterm birth. Of the 31 studies evaluating miscarriage, 28 showed a positive association between thyroid autoantibodies and miscarriage. Meta-analysis of the cohort studies showed more than tripling in the odds of miscarriage with the presence of thyroid autoantibodies (odds ratio 3.90, 95% confidence interval 2.48 to 6.12; P < 0.001). For case-control studies the odds ratio for miscarriage was 1.80, 1.25 to 2.60; P = 0.002). There was a significant doubling in the odds of preterm birth with the presence of thyroid autoantibodies (2.07, 1.17 to 3.68; P = 0.01). Two randomised studies evaluated the effect of treatment with levothyroxine on miscarriage. Both showed a fall in miscarriage rates, and meta-analysis showed a significant 52% relative risk reduction in miscarriages with levothyroxine (relative risk 0.48, 0.25 to 0.92; P=0.03). One study reported on the effect of levothyroxine on the rate of preterm birth, and noted a 69% relative risk reduction (0.31, 0.11 to 0.90).

CONCLUSION

The presence of maternal thyroid autoantibodies is strongly associated with miscarriage and preterm delivery. There is evidence that treatment with levothyroxine can attenuate the risks.

Thyroid autoimmunity and miscarriage: a meta-analysis

OBJECTIVE

To investigate whether thyroid autoimmunity (TAI) is associated with increased risk of miscarriage in euthyroid women.

METHODS

An electronic search was conducted using the databases Medline, PubMed, EMBASE and the Cochrane library, from inception to October 2010. A systematic review of the studies on the association between TAI and miscarriage was performed. The odd ratios of case-control studies and relative risks of cohort studies were pooled respectively. The software Review Manager (version 4.3.1) was applied for meta-analysis.

RESULTS

The search strategy identified 53 potentially relevant publications, 22 of which were included in the meta-analysis. A clear association between thyroid autoimmunity and miscarriage was observed with a pooled odds ratio of 2·55 (95% CI 1·42-4·57, P=0·002) in eight case-control studies and a pooled relative risk of 2·31 (95% CI 1·90-2·82, P<0·000 01) in 14 cohort studies. Women with TAI were found to have slightly higher age [age difference, 1·29 years] (95% CI 0·43-2·16, P=0·003) and thyroid-stimulating hormone (TSH) levels [TSH difference, 0·61 mIU/l] (95% CI 0·51-0·71, P<0·000 01) compared with those without TAI.

CONCLUSION

Based on the currently available evidence, it appears that the presence of thyroid autoimmunity is associated with an increased risk of spontaneous miscarriage in euthyroid women.

Thyroid function and pregnancy: before, during and beyond

Thyroid disturbances are common in women during the reproductive years of their lives. Autoimmunity and altered iodine status together account for a high proportion of the abnormalities. Autoimmune thyroid disease is present in around 4% of young females, and up to 15% are at risk because they are thyroid antibody-positive. There is a strong relationship between thyroid immunity on the one hand and infertility, miscarriage, and thyroid disturbances in pregnancy and postpartum on the other hand. Suboptimal iodine status affects a large proportion of the world's population, and pregnancy further depletes iodine stores. There is controversy surrounding the degree to which iodine should be supplemented and the duration of supplementation. Recent studies have helped to clarify the relationship between maternal thyroid status and neuropsychological development of the child. The role of other environmental factors including smoking and selenium status is also now recognised. Universal screening for thyroid hormone abnormalities is not routinely recommended at present. However, measurement of thyroid function and autoantibodies should certainly be considered in those who are at high risk of thyroid disease and in those whose pregnancy is otherwise high risk. The practicing clinician needs to be aware of the thyroid changes which accompany pregnancy.

Hashimoto's thyroiditis affects symptom load and quality of life unrelated to hypothyroidism: a prospective case-control study in women undergoing thyroidectomy for benign goiter

BACKGROUND

Hashimoto's thyroiditis (HT) is a common disease, and is the most prevalent cause of hypothyroidism. Symptoms and diseases associated with HT are considered to be caused by hypothyroidism. We hypothesized that higher antithyroperoxidase (anti-TPO) antibody levels would be associated with an increased symptom load and a decreased quality of life in a female euthyroid patient collective.

METHODS

In a prospective cohort study 426 consecutive euthyroid female patients undergoing thyroid surgery for benign thyroid disease were included. Main outcome measures were preoperative anti-TPO levels, a symptom questionnaire and the SF-36 questionnaire, and lymphocytic infiltration of the thyroid tissue as evaluated by histology.

RESULTS

Histology revealed HT in 28/426 (6.6%) subjects. To maximize the sum of the predictive values, a cut-off point for anti-TPO of 121.0 IU/mL was calculated (sensitivity 93.3% [95% confidence interval: 77.9%-99.0%]; specificity 94.7% [95% confidence interval: 92.0%-96.7%]) to predict the presence of histological signs of HT. The mean number of reported symptoms was significantly higher in patients with anti-TPO levels >121.0 IU/mL than in the other group (6.7 ± 2.5 vs. 4.1 ± 2.8; p < 0.001). There were no differences in preoperative thyroid-stimulating hormone levels (1.7 ± 1.3 vs. 1.5 ± 1.4 μU/mL, respectively; p = 0.155). Chronic fatigue, dry hair, chronic irritability, chronic nervousness, a history of breast cancer and early miscarriage, and lower quality-of-life levels were significantly associated with anti-TPO levels exceeding the cut-off point (p < 0.05).

CONCLUSIONS

Women with HT suffer from a high symptom load. Hypothyroidism is only a contributing factor to the development of associated conditions.

Effect of autoimmune thyroid disease in older euthyroid infertile woman during the first 35 days of an IVF cycle

In this case-control study of euthyroid first-cycle IVF patients ≥ 38 years old with singleton baby, miscarriage, biochemical pregnancy, and no pregnancy outcomes from 2005-2008, we assayed frozen serum for autoimmune thyroid disease (AITD) and thyroid function at cycle start, trigger, and 4 and 5 weeks' gestation. AITD prevalence in older infertile women was similar across clinical outcomes, and although AITD was associated with a higher baseline TSH, TSH remained within acceptable ranges, suggesting that T(4) supplementation may not affect maternal outcomes in older euthyroid AITD patients through 5 weeks gestation.

Thyroid function in women found to have early pregnancy loss

BACKGROUND

Pregnancy influences thyroid function and may bring to light mild and latent disorders. Thyroid dysfunction has been related to obstetrical complications such as premature delivery, gestational hypertension, preeclampsia, and placental abruption. The aim of our study was to evaluate whether the occurrence and timing of pregnancy loss could be related to thyroid autoimmunity or subclinical hypothyroidism (SH) per se.

METHODS

Two hundred sixteen apparently healthy pregnant women with no previous history of thyroid disease and with diagnosis of early miscarriage (before the 12th week of gestation) were enrolled. Miscarriages were classified as very early pregnancy loss (EPL) or embryo loss (crown rump length < or =10 mm) and EPL or fetal loss (crown rump length > 10 mm). Women were subdivided into four groups: euthyroid (ET), SH, overt hypothyroidism, and thyroid autoimmunity group.

RESULTS

One hundred seventy-six women had a normal thyroid function (84.6%), 24 patients were found to have positive thyroid antibodies (11.5%), 8 women (3.8%) an SH, and 8 cases were excluded. Thyroid-stimulating hormone levels were found to be higher in the very early (1.4 +/- 1.0 mU/L) than in the EPL group (1.1 +/- 0.7 mU/L) (p = 0.04), and in patients affected by SH (3.9 +/- 0.1 mU/L) compared to ET (1.0 +/- 0.5 mU/L) (p < 0.001) and autoimmune women (1.0 +/- 0.4 mU/L) (p < 0.001). Although the multivariate logistic regression analysis revealed that both autoimmunity and SH were independently correlated with the onset of very EPL, abortion was more precocious in the SH group (6.5 +/- 0.9 weeks), followed by the autoimmune (8.2 +/- 2.1 weeks) and ET groups (8.2 +/- 1.6 weeks) (p = 0.02).

CONCLUSIONS

Both thyroid diseases SH and autoimmune disorder are independently associated with very early embryo loss, but women suffering from SH have a lower gestational age at abortion.

[Thyroid disorders and pregnancy]

Disorders of the thyroid in women are common during the reproductive years. Incorrect or delayed treatment during pregnancy can adversely affect the health of mother and child. Knowledge of the physiological changes during this time is essential. Thyroid disorders, in particular hypothyroidism, may compromise fertility. Autoimmune thyroiditis is associated with a higher risk of fetal loss. In women on thyroid hormone replacement therapy, the thyroxine dose has to be adjusted to meet the enhanced requirement during pregnancy. Thyroid hormone is vital to fetal brain development. During pregnancy and lactation, iodine supplementation is also recommended due to alterations in iodine metabolism. Hyperthyroidism during pregnancy can adversely affect pregnancy outcome and has to be treated accordingly. Propylthiouracil should be given using the least effective dose to keep free thyroxine levels at the upper limit of normal or slightly above. Hyperthyroidism in the fetus and the neonate can be induced by thyroid stimulating antibodies capable of passing the placenta.

The role of thyroid autoimmunity in fertility and pregnancy

The thyroid gland and gonadal axes interact continuously before and during pregnancy. Hypothyroidism influences ovarian function by decreasing levels of sex-hormone-binding globulin and increasing the secretion of prolactin. In women of reproductive age, hypothyroidism can be reversed by thyroxine therapy to improve fertility and avoid the need for use of assisted reproduction technologies. For infertile women, preparation for medically assisted pregnancy comprises controlled ovarian hyperstimulation that substantially increase circulating estrogen concentrations, which in turn can severely impair thyroid function. In women without thyroid autoimmunity these changes are transient, but in those with thyroid autoimmunity estrogen stimulation might lead to abnormal thyroid function throughout the remaining pregnancy period. Prevalence of thyroid autoimmunity is significantly higher among infertile women than among fertile women, especially among those whose infertility is caused by endometriosis or ovarian dysfunction. Presence of thyroid autoimmunity does not interfere with normal embryo implantation, but the risk of early miscarriage is substantially raised. Subclinical and overt forms of hypothyroidism are associated with increased risk of pregnancy-related morbidity, for which thyroxine therapy can be beneficial. Systematic screening for thyroid disorders in pregnant women remains controversial but might be advantageous in women at high risk, particularly infertile women.

Thyroid autoimmunity, infertility and miscarriage

Thyroid autoimmunity (TAI), infertility and miscarriage are currently issues of extreme interest that have attracted the attention of many investigators. Several papers have been published, focusing on women of childbearing age that include healthy women, women with recurrent miscarriage and those undergoing assisted conception. Most of these studies show a significant association between the presence of thyroid autoantibodies, infertility and a higher miscarriage rate. The underlying pathogenetic mechanisms, which might explain the association between TAI and infertility, remain speculative given the scarce information from animal models and from in vitro data addressing the potential effects of TAI on fertility. Adequate levels of circulating thyroid hormones are of primary importance for normal reproductive function and inadequate delivery of triiodothyronine to granulosa and stromal cells may disrupt normal female reproductive function. With regards to the association between TAI and miscarriage, a close relationship has been largely confirmed in recent studies. The aim of this review is to present the relevant information published so far in the literature regarding TAI and miscarriage in euthyroid female individuals.

Obstetric management of thyroid disease

Timely treatment of thyroid disease during pregnancy is important in preventing adverse maternal and fetal outcome. At present, thyroid testing is performed on symptomatic pregnant women or those with a history of the disease. Hypothyroidism is very often subclinical in nature and not easily recognized without specific screening programs. Even mild maternal thyroid hormone deficiency may lead to neurodevelopment complications in the fetus. Early maternal thyroxine therapy might be beneficial in these women. The main diagnostic indicator of thyroid disease is the measurement of serum thyroid stimulating hormone and free thyroxine. Availability of gestation-age-specific thyroid stimulating hormone (TSH) thresholds is an important aid in the accurate diagnosis and treatment of thyroid dysfunction. Pregnancy-specific free thyroxine thresholds not presently available are also required. Gestational iodine deficiency is still prevalent in some areas of the United Kingdom. Thyroid peroxidase antibody (TPO Ab) in combination with thyroglobulin autoantibody (TgAb) is an accurate predictor of postpartum thyroiditis (PPT). Early screening and treatment of PPT may be justified on the grounds that it is relatively common and causes considerable postpartum morbidity. Large-scale intervention trials are urgently needed to assess the efficacy of preconception or early pregnancy screening for thyroid disorders.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader should be able to state that thyroid gland physiology changes with pregnancy, recall that levels of thyroid hormones are gestational-age related, and explain that accurate interpretation of both antepartum and postpartum levels of thyroid hormones are important in preventing pregnancy-related complication secondary to thyroid dysfunction and in the diagnosis and management of postpartum thyroiditis.

Subclinical hypothyroidism and thyroid autoimmunity in women with infertility

OBJECTIVE

To determine the prevalence of different subclinical hypothyroidism (SH) grades and thyroid autoimmunity (TAI) in infertile women.

DESIGN

Retrospective study. Setting. Endocrinology division of a public hospital in Argentina.

PATIENTS

Group I comprised 244 women consulting on infertility (>1 year without pregnancy); Group C (controls) comprised 155 healthy women with confirmed fertility.

INTERVENTION

Thyroid-stimulating hormone and thyroid peroxidase antibodies were measured in all patients, and a thyrotropin-releasing hormone (TRH) stimulation test was performed in 71 patients to diagnose SH grade 1. The pregnancy rate in hypothyroid women on levothyroxine treatment was also evaluated.

RESULTS

SH was diagnosed in 13.9% of the patients in Group I and in 3.9% of Group C (p < 0.002). The TRH stimulation test was useful to detect SH grade 1 in 12.7% of the infertile patients. Patients with precocious ovarian failure, tubal disturbances and ovulatory dysfunction presented higher SH rates (40.0, 18.2 and 15.4%, respectively) than control patients (p < 0.0001, p < 0.002 and p < 0.003). No significant difference in TAI prevalence was shown in Group I relative to Group C. Pregnancy rate of 44.1% was achieved under levothyroxine treatment.

CONCLUSIONS

We observed a higher prevalence of SH, but not of TAI, in patients with infertility. Our results support thyroid screening in women with reproductive failure.

Thyroid disease and female reproduction

The menstrual pattern is influenced by thyroid hormones directly through impact on the ovaries and indirectly through impact on SHBG, PRL and GnRH secretion and coagulation factors. Treating thyroid dysfunction can reverse menstrual abnormalities and thus improve fertility. In infertile women, the prevalence of autoimmune thyroid disease (AITD) is significantly higher compared to parous age-matched women. This is especially the case in women with endometriosis and polycystic ovarian syndrome (PCOS). AITD does not interfere with normal foetal implantation and comparable pregnancy rates have been observed after assisted reproductive technology (ART) in women with and without AITD. During the first trimester, however, pregnant women with AITD carry a significantly increased risk for miscarriage compared to women without AITD, even when euthyroidism was present before pregnancy. It has also been demonstrated that controlled ovarian hyperstimulation (COH) in preparation for ART has a significant impact on thyroid function, particularly in women with AITD. It is therefore advisable to measure thyroid function and detect AITD in infertile women before ART, and to follow-up these parameters after COH and during pregnancy when AITD was initially present. Women with thyroid dysfunction at early gestation stages should be treated with l-thyroxine to avoid pregnancy complications. Whether thyroid hormones should be given prior to or during pregnancy in euthyroid women with AITD remains controversial. To date, there is a lack of well-designed randomized clinical trials to elucidate this controversy.

Fausses couches spontanées précoces répétées : quelle prise en charge proposer en 2006 ?

More than 1% of the couples whishing children suffer from recurrent miscarriage, but investigations and treatment are not consensual. Most patients have several risk factors, and a minimum investigation of known factors has to be undertaken: karyotyping of the couple, hysteroscopy for searching uterine anatomic anomalies, evaluation for thrombophilias (anticardiolipin antibodies, lupus anticoagulant, protein C activity, Proteine S activity, factor V Leiden and factor II mutations, activated protein C resistance), antinuclear antibodies. Systemic diseases (like lupus) and endocrine abnormalities (like thyroid diseases and diabetes mellitus) have to be detected by clinical examination and questioning. No endocrine investigation is recommended, unless irregular menstruations or sterility. Research in recurrent pregnancy loss are conducted in new associated factors, such as skewed-X-chromosome inactivation, maternal HLA types, modifications in specific immune molecules and cells regulation. Therapeutic proposals are preimplantation genetic diagnosis in case of abnormal karyotiping, hysteroscopic surgery for septate uterus, aspirin plus heparin in antiphospholipid-positive patients, and aspirin plus corticosteroids in systemic lupus. Heparin seems to improve obstetrical prognosis for patients with congenital or acquired thrombophilias, but there are only few studies carried out on the subject. This new therapeutic approach should incite the patients with a negative medical appraisal to be referred to specialized consultations in order to include them in eventual clinical tests. Finally, empathic listening and psychological support are necessary in a pathology with multiple etiological factors.

Levothyroxine treatment in euthyroid pregnant women with autoimmune thyroid disease: effects on obstetrical complications

CONTEXT

Euthyroid women with autoimmune thyroid disease show impairment of thyroid function during gestation and seem to suffer from a higher rate of obstetrical complications.

OBJECTIVE

We sought to determine whether these women suffer from a higher rate of obstetrical complications and whether levothyroxine (LT(4)) treatment exerts beneficial effects.

DESIGN

This was a prospective study.

SETTING

The study was conducted in the Department of Obstetrics and Gynecology.

PATIENTS

A total of 984 pregnant women were studied from November 2002 to October 2004; 11.7% were thyroid peroxidase antibody positive (TPOAb(+)).

INTERVENTION

TPOAb(+) patients were divided into two groups: group A (n = 57) was treated with LT(4), and group B (n = 58) was not treated. The 869 TPOAb(-) patients (group C) served as a normal population control group.

MAIN OUTCOME MEASURES

Rates of obstetrical complications in treated and untreated groups were measured.

RESULTS

At baseline, TPOAb(+) had higher TSH compared with TPOAb(-); TSH remained higher in group B compared with groups A and C throughout gestation. Free T(4) values were lower in group B than groups A and C after 30 wk and after parturition. Groups A and C showed a similar miscarriage rate (3.5 and 2.4%, respectively), which was lower than group B (13.8%) [P < 0.05; relative risk (RR), 1.72; 95% confidence interval (CI), 1.13-2.25; and P < 0.01; RR = 4.95; 95% CI = 2.59-9.48, respectively]. Group B displayed a 22.4% rate of premature deliveries, which was higher than group A (7%) (P < 0.05; RR = 1.66; 95% CI = 1.18-2.34) and group C (8.2%) (P < 0.01; RR = 12.18; 95% CI = 7.93-18.7).

CONCLUSIONS

Euthyroid pregnant women who are positive for TPOAb develop impaired thyroid function, which is associated with an increased risk of miscarriage and premature deliveries. Substitutive treatment with LT(4) is able to lower the chance of miscarriage and premature delivery.

Thyroid function inside and outside of pregnancy: what do we know and what don't we know?

A workshop entitled, "The Impact of Maternal Thyroid Diseases on the Developing Fetus: Implications for Diagnosis, Treatment, and Screening," was held in Atlanta, Georgia, January 12-13, 2004. This paper reports on the session that examined the prevalence of thyroid dysfunction in reproductive-age women and the factors associated with abnormal function. For this session the following papers were presented: "Thyroidal Economy in the Pregnant State: An Overview," "The Prevalence of Thyroid Dysfunction in Reproductive-Age Women- United States," and "Risk Factors for Thyroid Disease: Autoimmunity and Other Conditions." These presentations were formally discussed by invited respondents and by others in attendance. Salient points from this session about which there was agreement include the following: physiologic changes associated with pregnancy require an increased availability of thyroid hormones by 40% to 100% in order to meet the needs of mother and fetus during pregnancy. In the first trimester of gestation the fetus is wholly dependent on thyroxine from the mother for normal neurologic development. For the maternal thyroid gland to meet the demands of pregnancy it must be present, disease-free, and capable of responding with adequate stores of iodine. Thyroid autoimmunity is common and may contribute to miscarriages, as well as to hypothyroidism. With sufficient iodine nutrition, autoimmune thyroid disease (AITD) is the most common cause of hypothyroidism. As of 1994, iodine nutrition in the United States appeared to be adequate, but its continued monitoring is essential.

Thyroid autoimmunity and the risk of miscarriage

Approximately one-third of all pregnancies end in miscarriage. The etiology of recurrent abortion remains unknown in approximately 50% of all women. In the early 1990s it was discovered that unselected euthyroid women who present with thyroid antibodies (thyroid peroxidase and thyroglobulin) in the first trimester of pregnancy have a two-four-fold increase in their miscarriage rates. The majority of studies investigating women with recurrent abortion have also found a significant increase in thyroid antibody positivity compared with controls. Although the etiology of miscarriage in thyroid antibody women remains unknown, recent data have revealed a potential direct effect of thyroglobulin antibodies on pregnancy loss in a murine model. Uncontrolled studies assessing the effect of levothyroxine on decreasing the miscarriage rate in euthyroid antibody positive women, have demonstrated a decreased miscarriage rate.