Thyroid autoantibodies are not associated with recurrent pregnancy loss

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.

Thyroid peroxidase in human endometrium and placenta: a potential target for anti-TPO antibodies

Autoimmune thyroid disease is the most common endocrine disorder during pregnancy. Thyroid autoantibodies (TAs) have been suggested to serve a role in implantation failure and spontaneous abortion. Until now, there are no data on the potential interaction of TAs with human reproductive organs. Here, we set out for the first time to test this hypothesis by studying the expression of thyroid peroxidase (TPO) at gene and protein level in human reproductive organs. Endometrial samples were taken from normal women, and placenta tissues were collected after full-term caesarian section. Expression of TPO messenger RNA (mRNA) was investigated by qRT-PCR. In addition, polyclonal anti-TPO antibodies were produced and the expression of TPO protein in mentioned tissues was evaluated by immunohistochemistry and Western blot analysis. The reactivity of anti-TPO antibody in human embryos was evaluated by immunofluorescent staining. For the first time, our study showed that TPO is expressed at gene and protein levels in endometrium and placenta. TPO expression was mainly localized to glandular and luminal epithelial cells in the endometrium. In placenta, the syncytiotrophoblasts and invasive trophoblast cells were the main cell types that expressed TPO protein. Specific band of approximately 110 kDa was observed in all endometrial and placental tissues by Western blot analysis. However, no expression of TPO protein was observed in human embryo. TPO expression in endometrium and placenta may explain higher frequency of abortion and infertility in patients with thyroid autoimmunity.

Relationship between anti-thyroid peroxidase antibody positivity and pregnancy-related and fetal outcomes in Euthyroid women: a single-center cohort study

BACKGROUND

Thyroid autoimmunity (TAI) and subclinical hypothyroidism (SCH) have been associated with poor pregnancy and fetal outcomes. However, whether euthyroid women with anti-thyroid peroxidase antibody (TPOAb) positivity have a higher risk of poor pregnancy and fetal outcomes is debatable. Therefore, this study aimed to investigate the association between TPOAb positivity and pregnancy-related and fetal outcomes in euthyroid women.

METHODS

In total, 938 pregnant women participated in this prospective cohort study. The euthyroid group included 837 pregnant women and the TPOAb-positive group included 101 euthyroid pregnant women. Serum TPOAb, thyroglobulin antibody (TGAb), thyroid-stimulating hormone (TSH), and free thyroxine (FT4) levels were assessed. Pregnancy and fetal outcomes included gestational diabetes mellitus, spontaneous abortion, premature rupture of membranes, hypertensive disorders of pregnancy, preterm birth, fetal distress, low birth weight, fetal macrosomia, and small for gestational age infant.

RESULTS

Logistic regression analysis showed TPOAb positivity was not associated with an increased risk of poor pregnancy or fetal outcomes in euthyroid women. However, TPOAb-positive euthyroid women pregnant with a female fetus were independently associated with preterm births (OR: 4.511, 95% CI: 1.075-18.926) after adjustment for potential confounding factors.

CONCLUSIONS

TPOAb positivity was not found to be associated with poor pregnancy-related or fetal outcomes in euthyroid women. However, in euthyroid women with a female fetus, TPOAb positivity was strongly associated with preterm births. The risk of preterm birth in the euthyroid women with TPOAb positivity should be emphasized in clinical practice.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02966405 . Registered on October 24th 2016 - Retrospectively registered.

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.

Maternal thyroid disease and its effects on the fetus and perinatal outcomes

Thyroid disease is common in women of childbearing age and can have significant effects on the development of the fetus and perinatal outcomes. Maternal thyroid hormone is critical for proper fetal neurodevelopment, and the fetus relies on thyroid hormone from its mother for the first half of pregnancy. Both overt maternal hypothyroidism and overt maternal hyperthyroidism have been shown to be associated with adverse effects on central nervous system gray matter and neurocognitive development of offspring as well as increased obstetrical risks. Treatment of overt thyroid conditions improves outcomes. Subclinical maternal hypothyroidism may increase adverse neurocognitive and obstetrical outcomes although data are conflicting. To date, treatment of subclinical hypothyroidism has not shown benefit. Subclinical hyperthyroidism is well tolerated in pregnancy. Thyroid autoantibodies alone may also affect neurodevelopment and obstetrical outcomes; however, recent data have shown no improvement with levothyroxine treatment. Several rare maternal genetic thyroid conditions can affect the fetus including a thyroid-stimulating hormone receptor mutation leading to hypersensitivity to human chorionic gonadotropin and thyroid hormone resistance. The thyroid plays a crucial role in fetal health and understanding it is important for optimal care.

Prevalence of thyroid autoimmunity and effect of levothyroxine treatment in a cohort of 1064 patients with recurrent pregnancy loss

RESEARCH QUESTION

Does initiating levothyroxine treatment based on thyroid-stimulating hormone (TSH) >2.5 mIU/l or thyroid autoimmunity improve pregnancy continuation rates in recurrent pregnancy loss (RPL) patients?

DESIGN

A retrospective cohort study of 1064 RPL patients, in which subjects were classified as either euthyroid (TSH 0.1 to ≤2.5 mIU/l), borderline-subclinical hypothyroid (borderline-SCH, TSH 2.5 to ≤4 mIU/l) or subclinical hypothyroid (SCH, TSH 4 to ≤10 mIU/l). For subjects with ≥2 pregnancy losses and a subsequent pregnancy with known outcome, a comparison was done of the pregnancy continuation rate past 10 weeks of treated and untreated borderline-SCH (n = 98) and untreated euthyroid (n = 279) subjects, and between subjects with positive (n = 18) and negative (n = 206) thyroid peroxidase (TPOAb tests) within the borderline-SCH and euthyroid groups.

RESULTS

72.7% were euthyroid (721/992), 19.4% (192/992) were borderline-SCH, and 5.4% (54/992) were subclinically hypothyroid (SCH). Of 401 women with a subsequent pregnancy of known outcome at 10 gestational weeks, 21% received treatment with levothyroxine. 57.7% of subjects had a TPOAb test, which was positive in 9.25% (37/400) in euthyroid, 16.5% (22/133) in borderline-SCH subjects and 35.3% (12/34) in SCH subjects. Treatment did not improve pregnancy continuation rates in borderline-SCH subjects (P = 0.392). There was no difference in pregnancy outcomes based on TPOAb status and treatment for borderline-SCH subjects (P = 0.4214), or based on TPOAb status for euthyroid subjects (P = 0.2668).

CONCLUSIONS

Treatment of hypothyroidism in pregnancy should be initiated based on a TSH >4 mIU/l. Treatment initiation based on thyroid autoimmunity or a TSH >2.5 mIU/l may result in overtreatment.

Autoimmune thyroid disease during pregnancy

Understanding of changes in thyroid function and the consequences of thyroid disease during pregnancy has rapidly grown in the past two decades, and revised American Thyroid Association guidelines on this topic were published in 2017. This Review explores the association between thyroid autoimmunity and complications during and after pregnancy. Thyroid autoimmunity refers to the presence of antibodies to thyroperoxidase or thyroglobulin, or thyroid-stimulating hormone receptor antibodies (TRAbs), or a combination of these, and is present in up to 18% of pregnant women. Thyroid antibodies in pregnant women with normal functioning thyroids (ie, euthyroid) have been associated with several complications, including miscarriage and premature delivery. Treatments to improve pregnancy outcomes are being studied. Whether thyroid antibodies are associated with infertility and assisted reproductive technology outcomes is unclear; although, treatment with low doses of levothyroxine, which is usually used to treat hypothyroidism, can be considered in such situations. Additionally, thyroid antibodies have been associated with other neonatal and maternal complications. All these associations require confirmation in larger prospective studies, and their pathogenic mechanisms need to be better understood. Post-partum thyroiditis is substantially more frequent in women who have thyroid antibodies during pregnancy than in those who do not have thyroid antibodies; however, whether treatment can prevent post-partum thyroiditis in women who are or have been antibody positive is unknown. Finally, TRAbs cross the placenta from the mother to the fetus and can cause fetal or neonatal hyperthyroidism. Therefore, women who are positive for TRAbs during pregnancy should be monitored.

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

BACKGROUND

Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2011, significant clinical and scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid disease in women during pregnancy, preconception, and the postpartum period.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations. The guideline task force had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid disease in pregnancy include recommendations regarding the interpretation of thyroid function tests in pregnancy, iodine nutrition, thyroid autoantibodies and pregnancy complications, thyroid considerations in infertile women, hypothyroidism in pregnancy, thyrotoxicosis in pregnancy, thyroid nodules and cancer in pregnant women, fetal and neonatal considerations, thyroid disease and lactation, screening for thyroid dysfunction in pregnancy, and directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid disease in pregnant and postpartum women. While all care must be individualized, such recommendations provide, in our opinion, optimal care paradigms for patients with these disorders.

Clinical aspects of hyperthyroidism, hypothyroidism, and thyroid screening in pregnancy

OBJECTIVE

To evaluate the peer-reviewed literature on hypothyroidism, hyperthyroidism, and thyroid autoimmunity in pregnancy.

METHODS

We review published studies on thyroid autoimmunity and dysfunction in pregnancy, the impact of thyroid disease on pregnancy, and discuss implications for screening.

RESULTS

Overt hyperthyroidism and hypothyroidism are responsible for adverse obstetric and neonatal events. Several studies of association suggest that either subclinical hypothyroidism or thyroid autoimmunity increase the risk of complications. One randomized controlled trial showed that pregnant women with subclinical hypothyroidism benefit from treatment in terms of obstetric and neonatal complications, whereas another study demonstrated no benefit in the intelligence quotient of babies born to women with subclinical hypothyroidism. Thyroid autoimmunity has been associated with increased rate of pregnancy loss, recurrent miscarriage, and preterm delivery.

CONCLUSION

Current guidelines agree that overt hyperthyroidism and hypothyroidism need to be promptly treated and that as potential benefits outweigh potential harm, subclinical hypothyroidism also requires substitutive treatment. The chance that women with thyroid autoimmunity may benefit from levothyroxine treatment to improve obstetric outcome is intriguing, but adequately powered randomized controlled trials are needed. The issue of universal thyroid screening at the beginning of pregnancy is still a matter of debate, and aggressive case-finding is supported.

Subclinical Hypothyroidism and Thyroid Autoimmunity Are Not Associated With Fecundity, Pregnancy Loss, or Live Birth

CONTEXT

Prior studies examining associations between subclinical hypothyroidism and antithyroid antibodies with early pregnancy loss and live birth suggest mixed results and time to pregnancy (TTP) has not been studied in this patient population.

OBJECTIVE

This study sought to examine associations of prepregnancy TSH concentrations and thyroid autoimmunity with TTP, pregnancy loss, and live birth among women with proven fecundity and a history of pregnancy loss.

DESIGN AND SETTING

This was a prospective cohort study from a large, randomized controlled trial that took place at four medical centers in the United States.

PATIENTS OR OTHER PARTICIPANTS

Healthy women, ages 18-40 y, who were actively attempting to conceive and had one or two prior pregnancy losses and no history of infertility were eligible for the study.

INTERVENTION

There were no interventions.

MAIN OUTCOME MEASURE

TTP, pregnancy loss, and live birth.

RESULTS

Women with TSH ≥ 2.5 mIU/L did not have an increased risk of pregnancy loss (risk ratio, 1.07; 95% confidence interval [CI], 0.81-1.41) or a decrease in live birth rate (risk ratio, 0.97; 95% CI, 0.88-1.07) or TTP (fecundability odds ratio, 1.09; 95% CI, 0.90-1.31) compared with women with TSH <2.5 mIU/L after adjustment for age and body mass index. Similar findings were observed for women with thyroid autoimmunity and after additional adjustment for treatment assignment.

CONCLUSIONS

Among healthy fecund women with a history pregnancy loss, TSH levels ≥ 2.5 mIU/L or the presence of antithyroid antibodies were not associated with fecundity, pregnancy loss, or live birth. Thus, women with subclinical hypothyroidism or thyroid autoimmunity can be reassured that their chances of conceiving and achieving a live birth are likely unaffected by marginal thyroid dysfunction.

Peripheral blood natural killer cells and mild thyroid abnormalities in women with reproductive failure

Abnormalities in peripheral blood natural killer (NK) cells have been reported in women with primary infertility and recurrent spontaneous abortion (RSA) and several studies have been presented to define cutoff values for abnormal peripheral blood NK cell levels in this context. Elevated levels of NK cells were observed in infertile/RSA women in the presence of thyroid autoimmunity (TAI), while no studies have been carried out, to date, on NK cells in infertile/RSA women with non-autoimmune thyroid diseases. The contribution of this study is two-fold: (1) the evaluation of peripheral blood NK cell levels in a cohort of infertile/RSA women, in order to confirm related data from the literature; and (2) the assessment of NK cell levels in the presence of both TAI and subclinical hypothyroidism (SCH) in order to explore the possibility that the association between NK cells and thyroid function is not only restricted to TAI but also to SCH. In a retrospective study, 259 age-matched women (primary infertility [n = 49], primary RSA [n = 145], and secondary RSA [n = 65]) were evaluated for CD56+CD16+NK cells by flow cytometry. Women were stratified according to thyroid status: TAI, SCH, and without thyroid diseases (ET). Fertile women (n = 45) were used as controls. Infertile/RSA women showed higher mean NK cell levels than controls. The cutoff value determining the abnormal NK cell levels resulted ⩾15% in all the groups of women. Among the infertile/RSA women, SCH resulted the most frequently associated thyroid disorder while no difference resulted in the prevalence of TAI and ET women between patients and controls. A higher prevalence of women with NK cell levels ⩾15% was observed in infertile/RSA women with SCH when compared to TAI/ET women. According to our data, NK cell assessment could be used as a diagnostic tool in women with reproductive failure and we suggest that the possible association between NK cell levels and thyroid function can be described not only in the presence of TAI but also in the presence of non-autoimmune thyroid disorders.

Controversies in the management of hypothyroidism during pregnancy

IMPORTANCE

In the last 3 years, we have witnessed the publication of multiple but conflicting guidelines on the management of hypothyroidism during pregnancy. Hypothyroidism is one of the most common endocrinopathies in reproductive-age and pregnant women. Given the prevalence of thyroid disease, it is highly likely that obstetricians will encounter and provide care for pregnant women with thyroid disease. Therefore, a review of current guidelines and management options is clinically relevant.

OBJECTIVES

Our goals are to review the changes in thyroid function during pregnancy, the options for testing for thyroid disease, the different categories of thyroid dysfunction and surveillance strategies among subspecialty societies, and the obstetric hazards associated with thyroid dysfunction and review the evidence for benefit of treatment options for thyroid disease.

EVIDENCE ACQUISITION

We reviewed key subspecialty guidelines, as well as current and ongoing studies focused on the treatment of hypothyroidism during pregnancy.

RESULTS

There are significant differences in the identification and management of thyroid disease during pregnancy among subspecialists. We present our recommendations based on the available evidence.

RELEVANCE

Evidence exists that obstetricians struggle with the diagnosis and treatment of hypothyroidism. According to recent surveys, the management of hypothyroidism during pregnancy is the number 1 endocrine topic of interest for obstetricians. A synopsis of recently published subspecialty guidelines is timely.

CONCLUSIONS

Recent, evidence-based findings indicate that obstetricians should consider modifying their approach to the identification and treatment of thyroid disease during pregnancy.

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.

The impact of thyroid function on intrauterine insemination outcome--a retrospective analysis

BACKGROUND

Hashimoto's thyroiditis is the most common endocrinopathy in premenopausal women, and is associated with various gynecological problems, including recurrent miscarriage and unexplained infertility. A possible influence of Hashimoto's thyroiditis on the success of intrauterine insemination seems likely, but has not been evaluated as yet. Therefore, the aim of our study was to retrospectively analyze the impact on intrauterine insemination outcome of thyroid function and markers suggestive for Hashimoto's thyroiditis.

METHODS

Retrospective cohort study in a tertiary care center of 540 women who underwent Intrauterine Insemination. The clinical pregnancy rate was the main outcome parameters. The following possible influencing factors were tested: thyroid-stimulating hormone (TSH); thyroid autoantibodies; age; body mass index; type of sterility (primary/secondary); parity; male factor; presence of PCO syndrome; ovulation induction; ovarian stimulation; and current thyroid medication.

RESULTS

The overall clinical pregnancy rate was 6.9% (37/540). Age, thyroid hormone supplementation for thyroid-stimulating hormone (TSH) levels>2.5 micro-IU/ml, and ovulation induction with HCG were significantly predictive in the multivariate analysis (p<0.05) as influencing factors for the pregnancy rate after intrauterine insemination.

CONCLUSIONS

Women undergoing intrauterine insemination seem to benefit from a strict thyroid hormone supplementation regimen in order to achieve lower TSH levels.

Screening for autoimmune thyroid disorders after spontaneous abortion is cost-saving and it improves the subsequent pregnancy rate

Background

Hypothyroidism and/or autoimmune thyroid disorders (AITD) may contribute to spontaneous abortions (SpA). Cost-effectiveness analyses of thyroid screening in women after SpA are lacking. Our aim was to evaluate the cost-effectiveness of screening for AITD and/or hypothyroidism and their treatment in women after SpA with regard to their reproductive health.

Methods

We performed a cross-sectional non-randomized study with follow-up in 2008–2011 in the settings of Departments of Endocrinology and Obstetrics/Gynecology of a university hospital. We enrolled 258 women after SpA before the 12th gestational week and followed them for a median of 3 years. At enrollment, serum concentrations of thyroid stimulatory hormone (TSH), antibodies to thyroid peroxidase (TPOAb) and free thyroxine (FT4) were measured and thyroid ultrasound performed. Women with overt hypothyroidism were treated with levothyroxine (n = 45; 61.6%) and women with subclinical hypothyroidism or euthyroid AITD were treated (n = 28; 38.4%) or left untreated (n = 38; 14.7%). Euthyroid women without signs of AITD served as controls (n = 147; 57.0%).

Results

Of the 38 untreated women with AITD and/or subclinical hypothyroidism, 8 (21.1%) reported secondary infertility as compared to 16/147 (10.9%) controls and 3/73 (4.1%) treated women (p = 0.021). Treatment was associated with an increased rate of successfully completed subsequent pregnancies (increment of 6 newborns/100 women) and a savings of €19,539/100 women. Total costs per successfully completed pregnancy were €1,189 in controls, €1,564 in the treated, and €2,488 in the untreated women.

Conclusions

Screening for thyroid disorders in women after SpA and treatment with levothyroxine is cost-saving and it improves the subsequent pregnancy rate.

Management of thyroid peroxidase antibody euthyroid women in pregnancy: comparison of the american thyroid association and the endocrine society guidelines

The presence of thyroid autoantibodies is relatively high in women of childbearing age. There is evidence that positive thyroperoxidase antibody even in euthyroid women may increase the risk of spontaneous and recurrent pregnancy loss and preterm delivery. However, the evidence is not enough to justify recommendation on the screening of pregnant women for thyroid autoantibodies or LT4 supplementation for reducing maternal or fetal complications. In this paper we reviewed the related evidence and compared the new guidelines of the American Thyroid Association and Endocrine Society with respect to the screening and management of positive thyroperoxidase antibody in euthyroid pregnant women. As there was no major contradiction or disagreement between the two guidelines, either one of two guidelines may be used by clinicians for the appropriate management of thyroid autoimmunity during pregnancy.

The correlation of autoantibodies and uNK cells in women with reproductive failure

There is conflicting evidence on the role of autoimmune disorders in reproductive failure, including recurrent miscarriage (RM) and recurrent implantation failure (RIF), after in vitro fertilisation (IVF). Several commonly studied autoimmune markers in women with reproductive failure include antiphospholipid antibodies (APAs), thyroid peroxidase antibodies (TPA) and uterine natural killer (uNK) cells. However, there have not been any studies that have examined the correlation of these markers in women with reproductive failure. To determine if women who tested positive for autoantibodies (APA and thyroid peroxidase antibodies) have significantly higher uNK cell numbers than women who tested negative for these antibodies, the percentage of stromal cells that stained positive for CD56 was identified by immunocytochemistry in endometrial biopsies from 42 women with unexplained RM (29 women tested negative for autoantibodies and 13 women tested positive for autoantibodies) and 40 women with unexplained RIF (30 women tested negative for autoantibodies and 10 women tested positive for autoantibodies). Biopsies were obtained on days LH+7 to LH+9. There was no significant difference in uNK cell numbers between women with unexplained RM who tested negative and those who tested positive for autoantibodies. Similarly, there was no significant difference in uNK cell numbers between women with unexplained RIF who tested negative and those who tested positive for autoantibodies. In women with reproductive failure the presence of autoantibodies does not appear to affect the numbers of uNK cells in the endometrium around the time of implantation.

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.

[Maternal autoimmune thyroid disease and pregnancy complication]

BACKGROUND/AIM

Thyroid disorders exert a great impact on pregnancy course and outcome. The aim of the study was to investigate impact of autoimmune thyroid disorders on pregnancy course and outcome, frequency of pregnancy complications and pregnancy loss.

METHODS

We followed 63 pregnancies prospectively during the period 1985-2007, 28 with hyperthyroid and 15 with hypothyroid autoimmune disorders, and 20 healthy pregnancies. Follow up included clinical, sonographic and laboratory investigations, including OGTT and postprandial glicemia.

RESULTS

There was no difference between previous preterm and term labor in the observed groups (chi2 = 2.309; p > 0.05). Analysis of previous early pregnancy loss showed no significance (chi2 = 4.918; p > 0.05), including varieties of spontaneous and missed abortion (Fisher, p < 0.05). The hypothyroid patients developed gestational diabetes more frequently than the controls (chi2 = 7.638; p = 0.022), which is not the case with hyperthyroid patients (chi2 = 1.078; p > 0.05), or between the groups with thyroid disorders (chi2 = 3.619; p > 0.05). There was no difference among the groups in developing pregnancy-induced hypertension (chi2 = 1.953; p > 0.05).

CONCLUSIONS

Controlling thyroid diseases reduces pregnancy complications. Development of gestational diabetes in hypothyroid patients requires controlling glycoregulation in all pregnant women with hypothyroidism.

Impact of first trimester and postpartum period thyroid autoantibodies on abortus incidence in Turkish pregnant women

OBJECTIVE

Abortus is a common problem and is observed approximately in one third of all pregnancies. In this study, we aimed to evaluate in euthyroid pregnant population the effect of thyroid autoantibodies of both first trimester and postpartum period on abortus incidence.

DESIGN AND METHOD

Euthyroid 128 pregnant women were included in the study. All pregnants were required having a history of maximum one abortus without any previous endocrinological, immunological disorders. Thyroid autoimmunity was defined as having serum levels of either antithyroidperoxidase or antithyroglobulin antibodies higher than 34 and 115 IU/ml, respectively.

RESULTS AND CONCLUSIONS

One hundred of 128 pregnant women (78.1%) had no thyroid autoantibodies, whereas 28 pregnant women (21.9%) had positivity for one of thyroid autoantibodies. One hundred pregnant women (78.1%) gave healthy births, whereas 28 (21.9%) had abortus. Abortus incidence was 28.6% in autoantibody positive group, whereas it was 20% in autoantibody negative group. Serum anti-Tg levels both in first trimester and both in postpartum period were higher in pregnants abortus group when compared with healthy births group. Although, we found no correlation between abortus incidence and thyroid autoantibodies presence, first trimester serum levels of anti-Tg levels may have correlated with abortus incidence and may be an indicator of a closer follow-up. In sight of this study, it can be concluded that autoimmunity against thyroid may continue after termination of pregnancy and this was the first study evaluating the postpartum antibodies levels which may be helpful in subsequent pregnancies.

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.

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.

Evaluation and management of recurrent early pregnancy loss

Recurrent pregnancy loss affects up to 5% of couples trying to establish a family. Evaluation classically begins after 3 consecutive miscarriages of less than 10 weeks of gestation but may be warranted earlier if a prior miscarriage was found to be euploid, or if there is concomitant infertility and/or advancing maternal age. The evaluation begins with an extensive history and physical, followed by a diagnostic screening protocol. Management must be evidence-based; unproven treatments should be avoided. If no factor is identified, many couples will still eventually have a successful pregnancy outcome with supportive therapy alone.

Recurrent miscarriage

Many human conceptions are genetically abnormal and end in miscarriage, which is the commonest complication of pregnancy. Recurrent miscarriage, the loss of three or more consecutive pregnancies, affects 1% of couples trying to conceive. It is associated with psychological morbidity, and has often proven to be frustrating for both patient and clinician. A third of women attending specialist clinics are clinically depressed, and one in five have levels of anxiety that are similar to those in psychiatric outpatient populations. Many conventional beliefs about the cause and treatment of women with recurrent miscarriage have not withstood scrutiny, but progress has been made. Research has emphasised the importance of recurrent miscarriage in the range of reproductive failure linking subfertility and late pregnancy complications and has allowed us to reject practice based on anecdotal evidence in favour of evidence-based management.

Influence of thyroid autoimmunity and maternal age on the risk of miscarriage

OBJECTIVES

Recently, studies have shown an association between antiperoxidase for the detection of thyroid autoimmunity (TAI) and abortion. Another point to be considered is the association of high risk of abortion and maternal age. The aim of the present study was to evaluate if the association between TAI and miscarriage could also be verified whether a population of unselected pregnant young women who normally present a low risk of miscarriage.

MATERIALS AND METHODS

We studied 534 pregnant women, by determining their serum thyroid antiperoxidase antibodies (TPO-Abs), thyrotropin (TSH) and free thyroxine (fT4) levels. Our end point was the pregnancy loss or live birth.

RESULTS

Age ranged from 12 to 49 years (mean +/- S.D.; 23.5 +/- 5.9). Of 534 women, 29 (5.4%) were TPO-Ab positive. TSH levels were significantly higher in TPO-Ab-positive women compared with TPO-Ab negative women (median; 1.9 versus 1.1; P = 0.001). Elevated TSH levels were found in 13.8% (4 of 29) of the TPO-Ab-positive women compared with only 2.4% (12 of 505) in the TPO-Ab-negative women. There were no significant differences in fT4 levels in relation with autoimmunity and risk of miscarriage. The overall risk of miscarriage was 2.4% (13 of 534). Risk of miscarriage was significantly higher among women older than 35 years (7.7%), TPO-Ab positive (10.3%) and presenting high levels of TSH (12.5%). These factors remained independently associated with the risk of miscarriage in full multivariate analysis.

CONCLUSIONS

We conclude that TAI is independently associated with is a higher risk of miscarriage in a population of unselected pregnant presenting a low risk of miscarriage.

The thyroid and pregnancy: a novel risk factor for very preterm delivery

The major cause of neonatal mortality and morbidity is preterm delivery in general (< 37 completed weeks), and especially very preterm delivery (< 32 completed weeks). The objective of this study is to determine if either thyroid hormonal dysfunction and/or the presence of thyroid autoantibodies in the mother are associated with an increased risk of preterm and/or very preterm delivery. Data were collected prospectively and analyzed as a nested-case control study. There were 953 delivered gravidas enrolled between 1996 and 2002. Samples were collected at entry to care and stored at -70 degrees C. Cases included all women with preterm delivery (n = 124). Controls (n = 124) were randomly selected from among the 829 women who delivered at term (> 37 completed weeks). All samples were assessed for thyroid stimulating hormone, thyroperoxidase antibody, and thyroglobulin antibody. Gravidas with high thyrotropin (TSH) levels had a greater than threefold increase in risk of very preterm delivery. In some analyses, gravidas who tested positive for thyroglobulin antibody at entry to prenatal care also had a better than twofold increased risk of very preterm delivery. There were no significant associations between TSH level or thyroglobulin antibody positivity and the risk of moderately preterm delivery.

Evidence-based care of recurrent miscarriage

Between 0.5 and 1.0% of couples experience recurrent pregnancy loss (RPL), which is defined as three or more consecutive miscarriages. Losses are classified as pre-embryonic (<5 weeks), embryonic (5-10 weeks) or fetal (>10 weeks). Genetic abnormalities are responsible for RPL in 2-4% of these couples. Inadequate progesterone production has been proposed a cause of RPL and progesterone is given to prevent miscarriage, despite a lack of supportive evidence. The factor V Leiden and prothrombin G20210A mutations are common inherited thrombophilias also associated with RPL. Antenatal thromboprophylaxis is sometimes recommended although no data exist regarding efficacy. Antiphospholipid syndrome is known to cause RPL and antenatal thromboprophylaxis reduces the risk of miscarriage. Uterine abnormalities might also result in RPL. About 50% of cases of RPL have no identifiable cause. Alloimmune incompatibility has been proposed as a cause for RPL in these women. The concept of alloimmune-related RPL has not been scientifically validated.

Thrombophilias and recurrent pregnancy loss: a critical appraisal of the literature

Thrombophilias are suggested to play a role in recurrent miscarriage. The aim of this study was to evaluate the literature of the past 10 years regarding the association between thrombophilias and recurrent miscarriage. We concluded that there is a large variety in applied study methodology. Therefore, we defined criteria for an adequate study on the relationship of thrombophilias on recurrent pregnancy loss: (i) no exclusion criteria for patients or at least the same criteria for patients and controls; (ii) a clear definition of the gestational age at previous losses; (iii) a well-described control group; (iv) clear description of the test methods and moment of testing; and (v) a clear description of the (non) significant differences or odds ratio between cases and controls. Eleven out of 69 studies fulfilled these criteria. Their results show significant higher serum homocysteine levels among women with a history of recurrent miscarriage. No relation was found between recurrent miscarriage and the methylenetetrahydrofolate reductase C667T mutation. No relation was observed for the levels of antithrombin, protein C and protein S. Seven studies on the association of factor V Leiden (FVL) and/or pathologic activated protein C ratio (pAPCR) showed that FVL may play a role in second trimester losses, as do antiphospholipid antibodies. Studies on the prothrombin gene mutation yielded conflicting results. Consequently, large prospective studies according to the aforementioned criteria are needed to establish if there is a relationship between thrombophilias and recurrent miscarriage at all. At present, there is only justification for testing for homocysteine levels, antiphospholipid antibodies and FVL in women with a history of recurrent miscarriage.

Mechanism of recurrent spontaneous abortions in women with mosaicism of X-chromosome aneuploidies

OBJECTIVE

To investigate the mechanism of recurrent miscarriages in women with mosaicism of X-chromosome aneuploidies.

DESIGN

Prospective case-control study.

SETTING

University-based reproductive clinic housed in a medical center with genetic laboratories.

PATIENT(S)

Eighteen women who experienced recurrent miscarriages and had mosaicism of X-chromosome aneuploidies; two control groups, one with a balanced structural autosomal rearrangement and the other without chromosomal abnormalities.

INTERVENTION(S)

Criteria were established for the diagnosis of low-grade X-chromosome mosaicism by using peripheral blood lymphocytes. Patients were evaluated for the pathogenesis of recurrent miscarriages. Their abortion rate was assessed, and each abortus was karyotyped.

MAIN OUTCOME MEASURE(S)

Abortion rate and karyotype of the abortus.

RESULT(S)

In comparison with patients with X-chromosome mosaicism with a balanced structural autosomal rearrangement, patients with X-chromosome mosaicism without a balanced autosomal structural rearrangement had a significantly higher incidence of diminished ovarian reserve (DOR) and had a somewhat higher prevalence of uterine anomalies. In comparison with controls without chromosomal abnormalities, the patients with a balanced autosomal structural rearrangement also had higher incidence of both conditions, but the differences were not statistically significant. At least two factors are implicated in recurrent miscarriages in women with X-chromosome mosaicism. Among them, DOR is the most prevalent (occurring in 44.4% of cases), followed by uterine anomalies (16.7% of cases). Cases with DOR had a higher abortion rate than did those without (68.6% vs. 44.1%). Cases with DOR also had a slightly higher rate of abnormal karyotypes in the abortus than did those without (73.7% vs. 42.9%).

CONCLUSION(S)

The oocytes of women with X-chromosome mosaicism are in a suboptimal state of development and are prone to embryonic lethality.

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.

Immune testing in fertility practice: truth or deception?

PURPOSE OF REVIEW

Much attention has been paid to the role of immunology in reproductive success or failure. Every step in the establishment of normal pregnancy has been implicated as a possible site of immune-mediated reproductive failure. The widespread testing of antiphospholipid, antinuclear, antithyroid, and antisperm antibodies, as well as generalized immune testing, have thus been employed to diagnose patients with otherwise unexplained infertility or recurrent pregnancy loss. Controversial data surrounding the widespread and variable use of immune testing in current fertility practice is reviewed to determine which tests are warranted based on sound scientific evidence. Because it is postulated that early miscarriage, when occult, could represent a failure of embryo implantation indistinguishable from unexplained infertility, this analysis of immune testing includes a discussion of patients with recurrent pregnancy loss.

RECENT FINDINGS

Despite the increased prevalence of abnormal immune testing associated with early reproductive failure, the most rigorous studies have not proven a cause and effect between these phenomena. There is wide variation and inconsistency regarding this association, depending upon which test(s) are employed, the study methodology used, and the patient population under study. The significance of selected immunological test abnormalities associated with early reproductive failure is uncertain.

SUMMARY

Great variability exists in identifying candidates for immune testing, determining which tests to order, interpreting the test results, and offering immunologic treatments. This review argues that the use of widespread immune testing in clinical practice can not be supported by existing data. The resulting therapies are similarly of unconfirmed benefit and may cause harm.