Presence of thyroid antibodies in early reproductive failure: biochemical versus clinical pregnancies**Presented at the 42nd Annual Meeting of the Pacific Coast Fertility Society, Indian Wells, California, April 20 to 24, 1994

Subclinical hypothyroidism in the infertile female population: a guideline

There is controversy regarding whether to treat subtle abnormalities of thyroid function in infertile female patients. This guideline document reviews the risks and benefits of treating subclinical hypothyroidism in female patients with a history of infertility and miscarriage, as well as obstetric and neonatal outcomes in this population.

Pre-Conceptional Anti-Thyroid Antibodies and Thyroid Function in Association with Natural Conception Rates

Thyroid functioning is an integral part of the endocrine system that supports conception and pregnancy. Frequent consumption of seafood and iodine by Japanese people may adversely affect their thyroid function. Thus, in this study, we aimed to analyze the associations between iodine intake, thyroid hormones, autoimmunity, and natural conception rates in Japanese women trying to conceive their first child. A prospective study of 24 weeks targeted 80 women with no history of infertility, who did not plan to undergo fertility treatment. Concentrations of urinary iodine concentration and thyroid biomarkers in the serum at enrollment were measured. Thirty-five women naturally conceived during the follow-up. The median (inter-quartile range) urinary concentration of iodine was 297 (165, 500) μg/L. Free triiodothyronine (T3) and free thyroxin (T4) negatively correlated with urinary iodine concentrations. Women with anti-thyroid peroxidase (anti-TPO) ≥ 16 IU/mL had lower conception rates (hazard ratio: 0.28, 95% confidence interval, 0.08-0.92) compared with those with anti-TPO < 16 IU/mL, after adjusting for age and coital frequency. None of anti-thyroglobulin antibody, free T3, free T4, or thyroid-stimulating hormone showed significant associations with conception rate after adjusting for age and coital frequency. The negative association between thyroid autoimmunity and natural conception rates warrants further investigation.

Interplay of immune components and their association with recurrent pregnancy loss

Maintenance and progression of pregnancy is an intricate process governed by a variety of developmental cues. Recurrent pregnancy loss (RPL) is a complication experienced by expecting mothers that is defined as three or more consecutive pregnancy losses. This review focuses on the dysfunctions of the immune system as one of the key contributors towards RPL. The current data suggests that the alloimmune and autoimmune factors contribute to the loss of fetus. Such causes despite being recognized as a definitive reason for recurrent pregnancy loss, are still under extensive investigation with new parameters being discovered and scrutinized for their association with RPLs. More in-depth and high throughput studies are required for devising better diagnostic tools and management strategies for the affected female so that they can carry their pregnancy to term.

The pathogenic role of circulating Hashimoto's Thyroiditis-derived TPO-positive IgG on fetal loss in naïve mice

PROBLEM

Antibody-mediated autoimmune diseases, such as autoimmune thyroid diseases (ATD), systemic lupus erythematosus (SLE), and antiphospholipid syndrome (APS), often are associated with recurrent fetal loss. One of the ATD is Hashimoto's thyroiditis which recently showed association with complications of pregnancy with increased levels of circulating autoantibodies reactive with epitopes on thyroid tissue such as thyroid peroxidase (anti-TPO). In retrospective study of sera analyses in patients with Hashimoto's thyroiditis, all patients had mainly elevated circulating anti-TPO autoantibodies.

AIM

We assessed the potential of human anti-TPO highly positive IgG, derived from patients with Hashimoto's thyroiditis sera associated with complications of pregnancy, to cause directly complications of pregnancy in murine model.

METHOD OF STUDY

Naïve ICR female mice, infused intravenously with 100 μg of anti-TPO-positive IgG, showed increased fetal loss and embryo small for date (P < .001) in comparison with mice passively transferred with commercial IgG or PBS. Moreover, we observed embryos small for date in the mice passively transferred with anti-TPO-positive IgG, exemplified by reduced weight of embryos and placentae (P = .001). Histopathological examination revealed delay in fetal development in 50% cases of anti-TPO-positive IgG-treated mice. Importantly, pathological changes in the transition zone, state of glycogen cells, and significant structural changes in the labyrinth part of placenta were observed in all anti-TPO-positive IgG samples.

CONCLUSION

The current study shows in the first time, a direct proof of concept, on the association of human TPO-positive IgG from Hashimoto's thyroiditis patients on fetal loss induction in murine model.

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.

Association of serum autoantibodies with pregnancy outcome of patients undergoing first IVF/ICSI treatment: A prospective cohort study

The relevance of antiphospholipid (aPL), antinuclear (ANA) or antithyroid (ATA) antibodies in women undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) are controversial. The present study aims to investigate which autoantibodies are associated with the pregnancy outcome of patients undergoing first IVF/ICSI treatment. A total of 3763 IVF/ICSI patients were recruited from January to December 2015. Forty-five patients positive for aPL presenting adverse outcomes in their first cycle received low-dose aspirin treatment before the second transfer. Logistic regression analyses were performed to assess any association between autoantibodies and IVF/ICSI outcomes. The aCL-IgG was significantly associated with live birth rate (OR 0.58, 95% CI 0.36-0.96, p<0.05) and miscarriage rate (OR 2.04, 95% CI 1.23-3.40, p<0.01). The aCL-IgM was associated with miscarriage rate (OR 2.14, 95% CI 1.29-3.54, p<0.01). The aβ₂GPI-IgG was associated with implantation rate and clinical pregnancy rate (OR 0.61, 95% CI 0.24-0.96, p<0.05; OR 0.40, 95% CI 0.13-0.87, p<0.05, respectively). After the low-dose aspirin treatment, the live birth rate (37.0% vs. 19.1%, p<0.05) increased significantly in patients with positive for aPL. In contrary, the aβ₂GPI-IgM, ANA, anti-thyroglobulin (aTG) and anti-thyroperoxidase (aTPO) antibodies had no association with IVF/ICSI outcome. It is suggested that the presence of aCL-IgG, aCL-IgM and aβ₂GPI-IgG might exert a detrimental effect on IVF/ICSI outcomes. Low-dose aspirin treatment could be useful for patients positive for these antibodies. Therefore, it is suggested that these antibodies should be assessed prior to IVF/ICSI treatment.

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.

The impact of thyroid autoimmunity on IVF/ICSI outcome: a systematic review and meta-analysis

BACKGROUND

Thyroid autoimmunity (TAI) is the most frequent autoimmune condition and the first cause of thyroid dysfunction among women of reproductive age. Notably, it has been associated with adverse obstetric outcomes during all trimesters of pregnancy. Furthermore, since most studies show an increased prevalence of TAI among women attending infertility clinics, a detrimental impact of this condition on natural fertility and on the rate of success of assisted reproductive techniques has been suggested. However, to date, the results have been inconsistent.

OBJECTIVE AND RATIONALE

The objective of this study was to define the relation between TAI per se and the outcome of in vitro fertilisation (IVF)/intracytoplasmic sperm injection (ICSI) cycles.

SEARCH METHODS

A systematic literature review and meta-analysis were conducted. A Medline search was performed to identify all the comparative studies published from January 1990 to November 2015 in the English language literature on IVF/ICSI outcome in women with and without TAI, using combinations of the medical subject heading terms 'thyroid autoimmunity', 'thyroid autoantibodies', 'IVF', 'ICSI', 'pregnancy', 'miscarriage' and 'delivery'. The primary outcome was live birth rate (LBR). Our secondary outcomes were number of oocytes retrieved (NOR), fertilisation rate (FR), implantation rate (IR), clinical pregnancy rate (CPR) and miscarriage rate (MR). We also extracted data on mean age and basal serum concentrations of thyroid stimulating hormone (TSH) and performed a meta-regression analysis to assess the effect of these two covariates on CPR and MR.

OUTCOMES

We selected 12 studies for the meta-analysis. Six of the included studies were prospective cohort studies, and six were retrospective cohort studies. Compared with women with negative TAI, women with positive TAI had a lower LBR (odds ratio (OR) 0.73; 95% confidence interval (CI) [0.54-0.99]; P = 0.04; 9 studies; 4396 women; I2 = 41%), a higher MR (OR 1.44; 95% CI [1.06-1.95]; P = 0.02; 12 studies; 4876 women; I² = 35%), a similar CPR (OR 0.90; 95% CI [0.77-1.06]; P = 0.22; 12 studies; 4876 women; I² = 7%), a similar number of oocytes (standardized mean difference [SMD] 0.10; 95% CI [-0.09 to 0.29]; P = 0.28; 5 studies; 1506 women; I² = 47%), a similar FR (OR 1.11; 95% CI [0.97-1.27]; P = 0.13; 3 studies; 1082 women; I² = 0%) and a similar IR (OR 0.98; 95% CI [0.73-1.32]; P = 0.91; 2 studies; 918 women; I² = 0%). Both mean age (SMD 0.96; 95% CI [0.66-1.27]; P < 0.00001; 9 studies; 3256 women; I² = 85%) and serum TSH (SMD 0.24; 95% CI [0.15-0.34]; P < 0.00001; 6 studies; 2098 women; I² = 59%) were higher in women with TAI. However, neither of these two covariates were significantly associated with CPR or MR.

WIDER IMPLICATIONS

TAI does not impact on IVF/ICSI outcome in terms of NOR and likelihood of fertilisation, implantation and clinical pregnancy. On the contrary, the presence of thyroid autoantibodies may have a detrimental effect on the course of a pregnancy, determining an increased risk of miscarriage and a decreased chance of live birth. However, given the possible modifying effects of age and serum TSH, further evidence is warranted prior to drawing inferences on causality.

Is there an effect of thyroid autoimmunity on the outcomes of assisted reproduction?

We aimed to evaluate the role of thyroid autoantibodies (TAA) on the outcomes of intracytoplasmic sperm injection-embryo transfer (ICSI-ET). A prospective case-control study was conducted in the in vitro fertilisation (IVF) centre of Suleymaniye Maternity Training and Research Hospital, Istanbul, Turkey between July 2013 and March 2014. A total of 49 (19.52%) TAA-positive and 202 TAA-negative patients were enrolled. Demographic characteristics and laboratory parameters were recorded. All patients underwent ICSI-ET. Thirty-one TAA-positive patients (32 cycles) and 121 TAA-negative patients (126 cycles) completed the study. Mean female age, body mass index (BMI), type of infertility, duration of infertility, antral follicle count (AFC), anti-Müllerian hormone (AMH), basal follicle stimulating hormone (bFSH), luteinising hormone (bLH), and oestradiol (bE2), prolactin and thyroid hormone profiles, male age and aetiology of infertility of both groups were similar (p > 0.05). There was no significant difference between groups in terms of duration and dose of gonadotropin (Gn) therapy, day of human chorionic Gn (hCG) administration, serum E2 and progesterone levels, number of collected oocytes, ratio of fertilisation, number of available embryos, positive pregnancy test, biochemical pregnancy, clinical pregnancy, ratio of miscarriage and ongoing pregnancy (p > 0.05). In conclusion, we failed to demonstrate a significant role of TAA on the outcomes of ICSI-ET in euthyroid patients. Further studies with larger numbers of participants are required to clarify these data.

Live birth rates following in vitro fertilization in women with thyroid autoimmunity and/or subclinical hypothyroidism

OBJECTIVE

To investigate whether the live birth rate following in vitro fertilization (IVF) is affected by thyroid autoimmunity (TAI) and/or subclinical hypothyroidism in subfertile women.

DESIGN AND SETTING

Retrospective study in a university infertility clinic.

PATIENTS

A total of 627 women without past or current history of thyroid disorder undergoing their first IVF cycle.

INTERVENTION

Pre-IVF archived blood serum samples were tested for TAI and thyroid function tests.

MAIN OUTCOME MEASURE

Live birth rate.

RESULTS

The clinical pregnancy rate, live birth rate and miscarriage rate were similar among women with or without TAI and/or subclinical hypothyroidism using a TSH threshold 4·5 mIU/l. Thyroid autoantibody level did not affect these IVF outcomes.

CONCLUSION

The live birth rate and miscarriage rate of women with TAI and/or subclinical hypothyroidism following IVF were not impaired.

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.

Miscarriage, and TNF-α and osteopontin relationship in women patients with Hashimoto's thyroiditis

OBJECTIVE

Infertility and reproductive impairment can be compromised by abnormalities in both endocrine and immune system. TNF-α promotes apoptotic cell death in fetal membrane tissues and pro-inflammatory, proapoptotic, and procoagulant properties of TNF-α probably contribute to widely accepted abortogenic profile of this cytokine. The aim of this study was to assess the alteration in the levels of TSH, FT3, FT4, TNF-α, osteopontin in pregnant and controls.

METHODS

Study subjects were 28 pregnant women, 28 non-pregnant women, and 28 healthy controls. All subjects underwent venous blood drawing for levels of TNF-α, osteopontin, and also hormonal assays including the levels of anti-TPO, anti-TG antibodies, TSH, FT3, FT4.

RESULTS

Both patient and control groups are similar in terms of age. Pregnancy age in conceived patients is 23.64 ± 2.040. No statistically meaningful relation was found in correlation analysis between TNF-α and osteopontin among the groups (p = 0.963). Anti-thyroglobuline antibody and anti-microsomal antibody levels were found to be higher in patients with non-pregnant patients with Hashimoto thyroiditis than the control group (p < 0.001). No statistically meaningful relation was found in terms of TNF-α (p = 0.66) and osteopontin serum levels (p = 0.50) in patient groups with or without miscarriage history.

CONCLUSIONS

In our study, no statistically meaningful relation was found in terms of TNF-α and osteopontin serum levels in patient groups with and without miscarriage history.

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 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 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.

Fetal rejection: infertility and immunity

Defective reaction toward fetal alloantigens could result in both recurrent spontaneous abortions (RSAs) and recurrent early pregnancy failures (REPFs), the latter existing in couples with unexplained infertility and multiple failures of implantation after in vitro fertilization embryo transfer. Immunological mechanisms leading to RSA and REPF seem to be different, although both syndromes probably have a genetic background that has not been identified so far. Despite the fact that antiphospholipid syndrome is a well-established cause of repeated pregnancy loss, the role of different autoantibodies existing in RSA and REPF patients needs to be elucidated. Immunotherapy is believed to correct the detrimental immune reactions; however, its real effectiveness and safety for the treatment of distinct forms of pregnancy loss need to be reconsidered.

Risk of spontaneous miscarriage in euthyroid women with thyroid autoimmunity undergoing IVF: a meta-analysis

OBJECTIVE

To investigate whether thyroid autoimmunity (TAI) is associated with increased risk for spontaneous miscarriage in subfertile, euthyroid women undergoing IVF.

DESIGN

Meta-analysis of observational studies.

PATIENT(S)

Four prospective studies that reported data on 1098 subfertile women undergoing IVF (141 with TAI and 957 controls) were included in the meta-analysis.

MAIN OUTCOME MEASURE

Miscarriage risk ratio (RR).

SECONDARY OUTCOME MEASURES

Clinical pregnancy rate and delivery rate.

RESULT(S)

Euthyroid, subfertile women with TAI undergoing IVF demonstrated significantly higher risk for miscarriage compared with controls (four studies-fixed effects RR: 1.99, 95% confidence interval: 1.42- 2.79, P<0.001). No significant difference in clinical pregnancy and delivery rates was detected between groups.

CONCLUSION

Based on the currently available evidence, it appears that the presence of TAI is associated with an increased risk for spontaneous miscarriage in subfertile women achieving a pregnancy through an IVF procedure.

A retrospective study on IVF outcome in euthyroid patients with anti-thyroid antibodies: effects of levothyroxine, acetyl-salicylic acid and prednisolone adjuvant treatments

BACKGROUND

Anti-thyroid antibodies (ATA), even if not associated with thyroid dysfunction, are suspected to cause poorer outcome of in vitro fertilization (IVF).

METHODS

We retrospectively analyzed: (a) the prevalence of ATA in euthyroid infertile women, (b) IVF outcome in euthyroid, ATA+ patients, and (c) the effect of adjuvant treatments (levothyroxine alone or associated with acetylsalicylic acid and prednisolone) on IVF results in ATA+ patients. One hundred twenty-nine euthyroid, ATA+ women undergoing IVF were compared with 200 matched, ATA-controls. During IVF cycle, 38 ATA+ patients did not take any adjuvant treatment, 55 received levothyroxin (LT), and 38 received LT +acetylsalicylic acid (ASA)+prednisolone (P).

RESULTS

The prevalence of ATA among euthyroid, infertile patients was 10.5%, similar to the one reported in euthyroid women between 18 and 45 years. ATA+ patients who did not receive any adjuvant treatment showed significantly poorer ovarian responsiveness to stimulation and IVF results than controls. ATA+ patients receiving LT responded better to ovarian stimulation, but had IVF results as poor as untreated ATA+ women. Patients receiving LT+ASA+P had significantly higher pregnancy and implantation rates than untreated ATA+ patients (PR/ET 25.6% and IR 17.7% vs. PR/ET 7.5% and IR 4.7%, respectively), and overall IVF results comparable to patients without ATA (PR/ET 32.8% and IR 19%).

CONCLUSION

These observations suggest that euthyroid ATA+ patients undergoing IVF could have better outcome if given LT+ASA+P as adjuvant treatment. This hypothesis must be verified in further randomized, prospective studies.

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.

Increased fetal abortion rate in autoimmune thyroid disease is related to circulating TPO autoantibodies in an autoimmune thyroiditis animal model

OBJECTIVE

To determine the fertility and abortion rates in a mouse model of autoimmune thyroiditis and its relationship with circulating anti-thyroid peroxidase (TPO) antibody.

DESIGN

Experimental animal study.

SETTING

University research laboratory.

ANIMAL(S)

C57bl/6 mice.

INTERVENTION(S)

Female C57bl/6 mice immunized with recombinant mouse TPO (rmTPO) in complete Freund adjuvant (CFA) or glutathione-S-transferase (GST-CFA) were allowed to mate. The pregnant mice were killed on day 14 of pregnancy for assessment of fetal development. The effects of TPO antibody on preimplantation embryo development and implantation rate were also studied.

MAIN OUTCOME MEASURE(S)

Litter size, resorption rate, preimplantation embryo development, and implantation rate.

RESULT(S)

All of the mice immunized with rmTPO-CFA possessed anti-TPO antibody. They had reduced litter size and increased incidence of resorbed fetus compared with the control. Higher serum TSH levels, but not T(4) levels, were demonstrated after rmTPO-CFA immunization. Anti-TPO antibody bound to preimplantation embryos. Treatment of the embryos with the antibody marginally decreased the formation of 3/4-cell embryos but had no effect on the subsequent development and implantation compared with the nonimmune control sera.

CONCLUSION(S)

Autoimmune thyroiditis is associated with reduced fertility and higher incidence of fetal loss. The anti-TPO antibody may affect post-implantation embryo development, leading to fetal loss.

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.

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.

Immunological analogy between allograft rejection, recurrent abortion and pre-eclampsia - the same basic mechanism?

There are still controversies concerning the role of immunological mechanisms engaged both in recurrent abortions (RA) and pre-eclampsia (PE). According to some opinions, recurrent miscarriage is comparable to organ-specific autoimmune disease. Analysis of immune reactions shows that graft rejection shares many similar mechanisms with RA and PE. This fact allows us to conclude that rejection of transplanted alloantigenic organs and pregnancy loss have probably the same evolutionary origin. Subsets and functions of immunocompetent cells (T CD4, suppressor gammadeltaT, cytotoxic T CD8, Treg, Tr1, uterine NK cells), over-activation of innate immunity (activation of NK cytotoxic cells, macrophages, neutrophils and complement), changes of Th1/Th2 cytokine balance (IL-2, IL-12, IL-15, IL-18, IFNgamma, TNFalpha vs. IL-4, IL-10, TGFbeta), importance of HLA-G molecule, CD200/CD200R interaction, over-expression of adhesion molecules, fgl2 prothrombinase activation and stimulation of IDO and HO expression, all suggest that RA and PE are syndromes of fetal allograft rejection, and not organ-specific autoimmune diseases. According to that supposition, an analogy might exist between acute graft rejection and recurrent abortion, and between chronic graft rejection and pre-eclampsia.

Diagnostic evaluation of women experiencing repeated in vitro fertilization failure

OBJECTIVE

The aim of the study was to propose a set of tests to clarify the diagnosis of repeated implantation failure in patients undergoing in vitro fertilization (IVF).

STUDY DESIGN

Fifty-nine patients with at least two unsuccessful IVF attempts were included in the study. Blood samples were evaluated for the presence of underlying thyroid abnormalities, antiphospholipid antibodies (aPL), increased levels of natural killer cells (NK), inherited thrombophilia and mouse embryo assay factor (MEA-f). The same tests were performed on 20 normal fertile control patients.

RESULTS

Seventy-six percent of IVF patients showed at least one abnormal result. This incidence was higher with respect to that found among control patients (45%). The prevalence of thyroid abnormalities, aPL and increased NK level was higher in IVF patients whereas no differences were observed in terms of prevalence of inherited thrombophilias and MEA-f.

CONCLUSIONS

A better understanding of reproductive failure mechanisms should allow an effective diagnostic flow chart and a focused therapeutic option for patients experiencing repeated IVF failure. With this objective in mind, our data provide two important results: thyroid abnormalities, aPL and increased NK levels are more prevalent in women experiencing IVF failure. No evidence was found for an association between inherited thrombophilia and MEA-f and failure to achieve pregnancy after IVF.

Thyroid disorders and pregnancy

During pregnancy physiologic changes in thyroid function occur which should not be misinterpreted as pathological. Thyroid disorders may complicate pregnancy and need thorough investigation and treatment in order to ensure a favourable pregnancy outcome. The incidence of hyperthyroidism in pregnant women has been reported to be approximately 0.2%. The leading cause is Graves' disease. Treatment of hyperthyroidism includes antithyroid drugs or surgery to avoid adverse effects on the neonate such as prematurity, intrauterine growth retardation and fetal or neonatal thyrotoxicosis. Use of radioactive iodine is contraindicated. Hypothyroidism during pregnancy is associated with gestational hypertension and low birth weight. Women on thyroid replacement therapy before pregnancy may require an increase in dosage during pregnancy. Pregnant women with chronic autoimmune thyroiditis have a higher incidence of spontaneous miscarriage. Nodular disease demands meticulous investigation to rule out a toxic adenoma or malignancy. Surgery in the case of cancer can be postponed under certain circumstances. Within one year following delivery, about 5-10% of women may exhibit postpartum autoimmune thyroid dysfunction, which may result in hypothyroidism.

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.

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.

Anti-thyroid Antibodies and Antiphospholipid Syndrome: Evidence of Reduced Fecundity and of Poor Pregnancy Outcome in Recurrent Spontaneous Aborters

PROBLEM

To determine the presence of anti-thyroid antibodies in patients with primary antiphospholipid syndrome (APS) [antiphospholipid antibodies (aPL) + recurrent spontaneous abortion (RSA)], compare APS alone with APS and thyroid autoimmunity for fecundity and for pregnancy outcome.

METHOD OF STUDY

A total of 203 non-pregnant women affected with primary APS were evaluated for anti-thyroid antibodies; 162 non-pregnant women affected with RSA and thyroid autoimmunity alone served as controls.

RESULTS

Anti-thyroid antibodies were found in 27% of APS patients studied. Patients with aPL alone had higher percentages of spontaneous pregnancies (P < 0.0001) and live births (P = 0.0003), when compared with patients positive for anti-thyroid antibodies alone or with aPL.

CONCLUSIONS

Thyroid autoimmunity is frequently present in APS recurrent aborters and is often associated with either reduced fecundity or with poor pregnancy outcome. Thyroid antibodies should always be evaluated in women with RSA including those with aPL.

Female infertility and the thyroid

Difficulty to conceive or subfertility constitutes a major psychological burden. Assisted reproductive technology changed significantly the outcome of couples faced with subfertility. These techniques consequently increased tremendously our understanding of the mechanisms underlying reproductive failure and opened new perspectives for future interventions, not only to increase cumulative conception rates after ART, but also spontaneous pregnancy rates. Thyroid dysfunction adversely affects fertility. Many studies imply a role for immunology, including thyroid autoimmunity in conception failure. In this review we attempt to update the available information on the adverse effect of thyroid dysfunction and/or thyroid autoimmunity on subfertility and we propose a rationale for testing and potential treatment options.

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.

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

The aim of this study was to determine the prevalence of autoimmune thyroid disease and the risk of miscarriage in autoimmune thyroid antibody (ATA)-positive women. Eight hundred seventy-six subjects completed the study, and 12.3% were thyroid antibody-positive (4.5% tested positive for both thyroid peroxidase antibody [TPO-Ab] and thyroglobulin autoantibody [Tg-Ab], 4.79% were TPO-Ab-positive only, and 3.1% were Tg-Ab-positive only). Fifty percent of the ATA-positive women and 14.1% of the ATA-negative group had a history of spontaneous abortion. Forty-eight of the ATA-positive women developed postpartum autoimmune thyroid dysfunction (PATD). Of these, 50% had hypothyroidism alone, 31.3% had transient hyperthyroidism followed by hypothyroidism, and 18.8% had transient thyrotoxicosis alone. Of the 48 PATD subjects, 12.5% developed persistent hypothyroidism. None of the ATA-negative women developed any form of thyroid dysfunction. The thyroid-stimulating hormone (TSH) levels in the ATA-positive group were significantly higher than those in the ATA-negative group, and only the ATA-positive women with a history of abortion had significantly higher TSH and lower free thyroxine (FT4) concentrations than the other subgroups. The results revealed a 5.5% prevalence rate for PATD in the study population. In addition to TPO-Ab, Tg-Ab is a useful marker for autoimmune thyroiditis.

Postpartum thyroiditis and autoimmune thyroiditis in women of childbearing age: recent insights and consequences for antenatal and postnatal care

Postpartum thyroiditis is a syndrome of transient or permanent thyroid dysfunction occurring in the first year after delivery and based on an autoimmune inflammation of the thyroid. The prevalence ranges from 5-7%. We discuss the role of antibodies (especially thyroid peroxidase antibodies), complement, activated T cells, and apoptosis in the outbreak of postpartum thyroiditis. Postpartum thyroiditis is conceptualized as an acute phase of autoimmune thyroid destruction in the context of an existing and ongoing process of thyroid autosensitization. From pregnancy an enhanced state of immune tolerance ensues. A rebound reaction to this pregnancy-associated immune suppression after delivery explains the aggravation of autoimmune syndromes in the puerperal period, e.g., the occurrence of clinically overt postpartum thyroiditis. Low thyroid reserve due to autoimmune thyroiditis is increasingly recognized as a serious health problem. 1) Thyroid autoimmunity increases the probability of spontaneous fetal loss. 2) Thyroid failure due to autoimmune thyroiditis-often mild and subclinical-can lead to permanent and significant impairment in neuropsychological performance of the offspring. 3) Evidence is emerging that as women age subclinical hypothyroidism-as a sequel of postpartum thyroiditis-predisposes them to cardiovascular disease. Hence, postpartum thyroiditis is no longer considered a mild and transient disorder. Screening is considered.

Thyroid autoantibodies

Although assays to detect thyroid autoantibodies have been available for more than 40 years, their place in the clinical management of thyroid disease has remained controversial; however, novel automated detection techniques using recombinant antigens are increasing the sensitivity and specificity of the assays, particularly for antibodies to the TSH receptor. In addition, new antigenic targets have been defined including the sodium-iodide symporter and four eye muscle proteins targeted in Graves' ophthalmopathy. This article summarizes the immunobiology, assay methodology and prevalence in thyroid diseases of each of the major thyroid autoantibodies before discussing the clinical indications for their use in thyroid diseases.

Thyroid antibodies and fetal loss: an evolving story

This article reviews the literature on thyroid antibodies and miscarriage. In 1990, in a study designed to determine the incidence and etiology of postpartum thyroiditis, a serendipitous finding emerged revealing an association between thyroid antibodies and spontaneous miscarriage. Subsequently, four other studies, performed on three different continents, have confirmed the correlation. Six studies have evaluated the relationship between thyroid antibodies and recurrent abortion, defined as three or more spontaneous miscarriages. The majority of the studies (67%) reported a statistically significant increase in the incidence of thyroid antibodies in the recurrent abortion group as compared to controls. Four intervention trials have evaluated the impact of immunosuppressive therapy in women with thyroid antibodies. Although all of the trials revealed a decrease in the incidence of recurrent abortion, each study was limited by methodological concerns. A recently developed murine model of pregnancy has also demonstrated increased fetal loss in female mice immunized with thyroglobulin when mated with allogeneic males. The implications of these data generated over the last decade are discussed.

Thyroid disease in relation to pregnancy: a decade of change

Inspection of the references cited in this review indicates that much work has occurred in the area of thyroid and pregnancy during the last decade. Significant advances in our understanding of the immunology of pregnancy and the effect of thyroid disease on this process have taken place. The role of hCG in the physiology of pregnancy and its relevance to thyroid function has been an emerging theme. There is still no clear explanation for the association between thyroid antibodies and infertility or miscarriage. During the last decade a general concensus has developed in relation to the management of hyperthyroidism in pregnancy although there are still variations in antithyroid drug use at this time. The aetiological classification of congenital hyper- and hypothyroidism utilizing new technologies has opened up a new perspective on these disorders. Attention has been drawn to the importance of treating maternal hypothyroidism with adequate thyroid replacement therapy and to the possibility of impaired child neuropsychological development consequent on low maternal thyroid hormone concentration in early gestation in non iodine deficient areas. Significant advances have been made during the last decade in the description of the clinical features and in our understanding of the pathogenesis of postpartum thyroid disease. The importance of long-term follow up of selected patient groups has also been emphasized.

Recognizing, understanding, and treating postpartum thyroiditis

Postpartum thyroiditis is the most common endocrinologic disorder, with an incidence that varies geographically from 5% to 10%. It has important clinical sequelae including symptoms of hyperthyroidism, hypothyroidism, and depression. Long-term follow-up of women who experience postpartum thyroiditis reveals a high recurrence rate in subsequent pregnancies. Postpartum thyroiditis is an autoimmune disorder, and thyroid antibody-positive women in the first trimester have a 33% to 50% chance of developing thyroiditis in the postpartum period. Whether or not to screen for postpartum thyroiditis remains controversial.

Antithyroid antibodies do not affect pregnancy outcome in women undergoing assisted reproduction

The purpose of this study was to determine the association of antibodies to thyroglobulin and thyroid peroxidase and pregnancy outcome in women undergoing assisted reproductive techniques. The study included three centres and retrospectively evaluated patient sera for antithyroid antibodies, then related the results to pregnancy outcome. Enzyme-linked immunosorbant assays for thyroglobulin and thyroid peroxidase antibodies were performed using two different commercially available kits. Controls included 200 healthy women of reproductive age. Women (n = 873) who were undergoing assisted reproductive techniques for pelvic adhesions, endometriosis, ovarian dysfunction, or unexplained/other were included. All women utilized a standard regimen of gonadotrophin releasing hormone agonist down-regulation followed by ovulation induction. Embryos were cultured for 3 days, at which time embryo transfer occurred. Statistical analysis utilized the two-tailed Fisher's exact test. Antithyroid antibodies were positive in 143 of 873 (16.4%) women undergoing assisted reproductive techniques while 29 of 200 (14.5%) normal controls were positive (not significant). Deliveries were achieved in 396 of 730 (54.2%) of women who had no thyroid antibodies versus 78 of 143 (54.5%) of women who had thyroid antibodies (not significant). No difference in biochemical pregnancies (not significant) or clinical pregnancy losses (not significant) were detected. Antithyroid antibodies were found no more frequently in women undergoing assisted reproductive techniques than in normal controls. There were no differences in pregnancy outcome based on antithyroid antibody positivity in women undergoing assisted reproductive techniques. These data do not support the testing or treatment for antithyroid antibodies of women undergoing assisted reproductive techniques.

Increased prevalence of antithyroid antibodies identified in women with recurrent pregnancy loss but not in women undergoing assisted reproduction

OBJECTIVE

To assess the prevalence of antibodies to thyroglobulin and thyroid peroxidase (or microsomal) in women with recurrent pregnancy loss and women undergoing assisted reproductive techniques (ART) compared with healthy controls.

DESIGN

Retrospective, two-centered study.

SETTING

University-affiliated private patient centers.

PATIENT(S)

Included were 700 women with a history of two or more consecutive pregnancy losses, 688 women with a history of infertility who were undergoing ART, and 200 healthy, reproductive-aged female controls.

INTERVENTION(S)

Blood was collected before ART cycles, frozen, and assayed.

MAIN OUTCOME MEASURE(S)

Standardized ELISAs were used to measure antithyroid antibodies and TSH levels. Statistical analysis was performed with use of the two-tailed Fisher's exact test.

RESULT(S)

Antithyroid antibodies were identified in 29 of 200 (14.5%) of controls and 158 of 700 (22.5%) of women with recurrent pregnancy loss and 132 of 688 (19.2%) of women undergoing ART. Less than 20% of the women with antithyroid antibodies were clinically hypothyroid.

CONCLUSION(S)

Antithyroid antibodies are identified more frequently in women with recurrent pregnancy loss than in controls but not in women undergoing ART. These autoantibodies may be markers of autoimmune activation and have been associated with an increased risk of pregnancy loss and postpartum thyroid disease.

Ovarian autoimmunity: greater frequency of autoantibodies in premature menopause and unexplained infertility than in the general population

The objective of this study was to: (1) assess the relative prevalence of ovarian, thyroid, nuclear, and cardiolipin antibodies associated with premature menopause and unexplained infertility and (2) compare ovarian and thyroid antibodies in premature menopause, unexplained infertility, and the general population. Autoantibodies were evaluated in women with premature menopause (n = 30), unexplained infertility with (n = 38) or without (n = 15) prior gonadotropin-induced ovulation, and normal cycling controls (n = 12) and in a population of women obtained from a blood bank (n = 53). Antibodies to ovary (OVAB), thyroid (THYAB; thyroid peroxidase and thyroglobulin), cardiolipin, and eight nuclear antigens were assessed by enzyme immunoassay. Organ-specific antibodies (ovary and thyroid) were present with significantly greater frequency than non-organ-specific antibodies (nuclear and cardiolipin) in premature menopause and unexplained infertility (60% (50/83) vs 16% (13/83) respectively; P < 0.0001). OVAB (53%, 44/83) were significantly more frequent than THYAB (30%, 25/83) in premature menopause and unexplained infertility (P = 0.0030). THYAB did not differ among all groups (P = 0.78). In premature menopause and treated or untreated unexplained infertility OVAB frequencies were 53, 61, and 33%, respectively, and were significantly more frequent than in the population (17%) (P = 0.0001). In unexplained infertility, individuals with no prior gonadotropin-induced ovulation had a lower frequency of OVAB than treated individuals (P = 0.07). The frequency distribution of optical density values for OVAB was significantly higher for premature menopause and unexplained infertility than for population or normal cycling women (P < 0.0001). Thus, only ovarian antibodies were significantly more frequent than other antibody markers of autoimmunity in premature menopause and unexplained infertility.

Thyroid antibody titer and avidity in patients with recurrent miscarriage

OBJECTIVE

To determine whether the titer and avidity of the thyroid peroxidase antibody differs between pregnant women in their first trimester who have a history of recurrent miscarriage and whose pregnancies continue to term and those whose pregnancies fail again later in the first trimester.

DESIGN

Controlled clinical study.

SETTING

Healthy volunteers in an academic research environment.

PATIENT(S)

Pregnant women in their first trimester who had a history of recurrent miscarriage (> or = 3 miscarriages) and who were known to be positive for the thyroid peroxidase antibody.

INTERVENTION(S)

None of the patients received any medication.

MAIN OUTCOME MEASURE(S)

Thyroid peroxidase antibody titer and avidity (i.e., the net binding strength between antibody and antigen).

RESULT(S)

At the time of presentation, thyroid peroxidase antibody titer and avidity was significantly higher in those women who later miscarried compared with those whose pregnancies continued. In those whose pregnancies continued to term, titer and avidity declined as the pregnancy progressed.

CONCLUSION(S)

Autoimmunity plays a role in recurrent miscarriage. Among a group of patients who had had recurrent miscarriages, there appeared to be differences in the humoral response to the pregnancy between those whose pregnancies continued to term and those whose pregnancies failed again.

Thyroid autoimmunity and abortion: a prospective study in women undergoing in vitro fertilization

OBJECTIVE

To determine whether an association exists between the presence of thyroid peroxidase (TPO) antibodies before pregnancy and miscarriage in women without a history of habitual abortion.

DESIGN

Prospective study and nested case-control study.

SETTING

Inner-city teaching hospital.

PATIENT(S)

Four hundred eighty-nine women in an IVF program.

INTERVENTION(S)

In the prospective study, we measured levels of TPO antibodies and TSH. In the nested case-control study, we also measured levels of anticardiolipin antibodies.

MAIN OUTCOME MEASURE

Miscarriage.

RESULT(S)

One hundred seventy-three women were observed, of whom 31% (54/173) became pregnant. Pregnancy occurred in 48% (12/25) of the antibody-positive women and in 28% (42/148) of the antibody-negative women. Among those who became pregnant, miscarriage occurred in 33% (4/12) of TPO antibody-positive women and in 19% (8/42) of TPO antibody-negative women. The TSH level was abnormal (<0.2 microIU/mL) in only one of the TPO antibody-positive women who miscarried. The presence of anticardiolipin antibodies was not associated with miscarriage.

CONCLUSION(S)

No association was found between the presence of TPO antibodies before pregnancy and miscarriage in women without a history of habitual abortion. The presence of TPO antibodies did not adversely affect a woman's chances of becoming pregnant.