Association of TSH concentrations and thyroid autoimmunity with IVF outcome in women with TSH concentrations within normal adult range

The effect of levothyroxine and prednisolone treatment on pregnancy in in vitro fertilization patients with positive thyroid autoantibodies

AIM

To investigate the effects of levothyroxine and prednisolone treatment, or in combination, on positive thyroid autoantibodies in infertile patients undergoing in vitro fertilization (IVF) therapy.

METHODS

This retrospective study included a total of 190 patients with positive thyroid autoantibodies (anti-T and anti-TPO) who underwent IVF treatment between January 2008 and March 2016. Patients were divided into four groups: group 1-levothyroxine group (n = 50), group 2-prednisolone group (n = 50), group 3-levothyroxine and prednisolone combination (n = 25), group 4-control group (n = 65). Anti-T and anti-TPO levels before IVF and at the time of embryo transfer (ET), b-hcg positivity, clinical and biochemical pregnancy, miscarriage rate, and live birth rate were compared among groups.

RESULTS

In levothyroxine-treated group, mean anti-TPO levels significantly decreased at the time of ET compared to before IVF treatment levels (p = 0.036). In group 3, mean anti-T and anti-TPO levels significantly decreased at the time of ET compared to levels before IVF treatment (p < 0.05). Patients who became pregnant in group 1, mean anti-T anti-TPO levels significantly decreased compared to before IVF treatment levels (p < 0.05). The biochemical pregnancy rate was significantly higher in group 2 (p = 0.03). Abortion rates were the highest in group 3, but no significant difference was found among groups. The group treated with levothyroxine had a significantly increased rate of live birth compared to the control group (p = 0.02).

CONCLUSIONS

Levothyroxine addition during IVF treatment of patients with positive thyroid antibodies in subclinical hypothyroidism increases the take-home baby pregnancy rate. Whether subclinical hypothyroidism or not in IVF treatment, levothyroxine is more effective than low-dose corticosteroids.

TPOAb positivity can impact ovarian reserve, embryo quality, and IVF/ICSI outcomes in euthyroid infertile women

The aim of this study was to investigate the effects of positive anti-thyroid peroxidase (TPO) antibodies on fertility, embryo quality, and pregnancy outcomes in women with normal thyroid function. A cross-sectional study of 1223 infertile women who received assisted reproductive technology (ART) treatment for the first time was conducted at our hospital from January 2019 to March 2022. Overall, 263 infertile women were included, comprising 263 cycles and 1813 embryos, and were divided into a positive group and a control group based on TPO antibody levels. The positive group was further divided into two subgroups according to the median antibody titer, and the therapeutic indices and pregnancy outcomes for each group were compared. The results showed that the AMH level in the positive group was significantly lower than that in the control group (2.37 (1.26-3.63) ng/ml vs. 3.54 (1.74-5.41) ng/ml, p < 0.001). The high-quality embryo rate (40.04% vs. 45.49%, p = 0.034) and live birth rate (23.26% vs. 36.16, p = 0.035) of the positive group were lower than those of the control group; the miscarriage rate was higher than that of the control group (37.50% vs. 17.95%, p = 0.035). The live birth rate in the low-titer group was significantly higher than that in the high-titer group (32.56% vs. 13.95%, p = 0.041). Studies have shown that positive anti-thyroid peroxidase antibodies are associated with a decreased ovarian reserve and decreased embryo quality. High titers of anti-thyroid peroxidase antibodies can reduce the live birth rate.

Impact of thyroid autoantibodies and serum TSH level on clinical IVF outcomes

OBJECTIVE

This study aimed to investigate the impact of thyroid autoantibodies and serum TSH levels on clinical IVF outcomes.

MATERIALS AND METHODS

This study included 260 Korean women scheduled for their first IVF between 2013 and 2017. Serum levels of thyroid hormone, TSH, and antibody for thyroid peroxidase and thyroglobulin were measured just before the first ovarian stimulation. Clinical pregnancy rate (PR), ongoing PR, and miscarriage rate were analyzed according to thyroid autoimmunity and serum TSH levels. The primary outcome was ongoing PR beyond 12 weeks of gestation.

RESULTS

The ongoing PR and miscarriage rates were similar between women with positive (n = 29) and negative autoantibodies (n = 186). In women with subclinical hypothyroidism (serum TSH ≥4.2 μIU/mL), ongoing PR was significantly lower than euthyroid women (22.2%, vs. 44.7%, p = 0.045), but miscarriage rate was similar. The group with serum TSH ≥3.4 μIU/mL showed a significantly lower ongoing PR (23.9% vs. 46.7%, p = 0.005) and significantly higher miscarriage rate (38.9% vs. 14.1%, p = 0.020). In multivariate logistic regression analysis, serum TSH ≥3.4 μIU/mL was an independent unfavorable predictor for ongoing PR (odds ratio 0.375, p = 0.013).

CONCLUSION

Thyroid autoantibodies did not affect clinical IVF outcomes, but women with serum TSH ≥3.4 μIU/mL demonstrated poor IVF outcomes.

Impact of thyroid autoimmunity and vitamin D on in vitro fertilization/intracytoplasmic sperm injection outcomes among women with normal thyroid function

This prospective cohort study aimed to determine the impact of thyroid autoimmunity and total 25-hydroxyvitamin D concentration on early pregnancy outcomes in women undergoing in vitro fertilization/intracytoplasmic sperm injection who had intact thyroid function. The study included 1,297 women who underwent in vitro fertilization/intracytoplasmic sperm injection cycles, although only 588 patients received fresh embryo transfer. The study endpoints were clinical pregnancy, ongoing pregnancy, ectopic pregnancy, and early miscarriage rates. Our study found that the total 25-hydroxyvitamin D serum concentrations (P<0.001) and anti-Mullerian hormone levels (P=0.019) were lower among patients in the TAI group (n=518) than among those in the non-TAI group (n=779). Additionally, the study population in each group was divided into three subgroups according to the total vitamin D status based on clinical practice guidelines (deficient, <20 ng/mL; insufficient, 21-29 ng/mL; and sufficient, ≥30 ng/mL), TAI group: sufficient, n=144; insufficient, n=187; and deficient, n=187; non-TAI group: sufficient, n=329; insufficient, n=318, and deficient, n=133. In the TAI group, the number of good-quality embryos decreased in patients with vitamin D deficiency (P=0.007). Logistic regression analysis indicated that aging prevented women from achieving clinical (P=0.024) and ongoing pregnancy (P=0.026). The current findings suggest that patients with TAI had reduced serum vitamin D concentration. Furthermore, in the TAI group, the number of good-quality embryos decreased in patients with vitamin D deficiency. Finally, aging adversely impacted achieving clinical and ongoing pregnancy.

Impact of thyroid autoimmunity on pregnancy outcomes in euthyroid women following fresh/frozen-thawed embryo transfer

OBJECTIVE

To investigate whether thyroid autoimmunity (TAI) is associated with assisted reproductive technology (ART) outcomes in euthyroid women undergoing fresh embryo transfer (ET) and frozen-thawed embryo transfer (FET).

DESIGN

A retrospective cohort study. Pregnancy and neonatal outcome after fresh ET or FET were compared between the positive and negative thyroid autoimmune antibody groups.

PATIENTS

A total of 5439 euthyroid women who started their ART cycle at our centre between 2015 and 2019 were included.

RESULTS

The thyroid antibody positive group had a greater mean age than the thyroid antibody negative group (32(29,35) vs. 31(28,34), p < .001). Women with positive thyroid antibody presented with a higher prevalence of diminished ovarian reserve (DOR) (9.1% vs. 7.1%, p = .026) and lower number of oocyte retrieved (9(5,15) vs. 10(6,15), p = .020), but difference was not significant after adjusting for age. The pregnancy rate, live birth rate, pregnancy loss rate, preterm delivery rate and low birthweight rate between the thyroid antibody positive and thyroid antibody negative groups were comparable both in fresh ET cycles and FET cycles. Subanalysis of the treatment outcomes when using a stricter threshold of TSH of 2.5 mIU/L showed no difference to that achieved when using an upper limit of 4.78 mIU/L.

CONCLUSIONS

The present study reveals that patients with anti-thyroid peroxidase antibodies (TPOAbs) and/or antithyroglobulin antibodies (TgAbs) showed no significant differences in pregnancy outcomes following fresh ET and FET when compared with patients with negative thyroid antibodies.

High level of thyroid peroxidase antibodies as a detrimental risk of pregnancy outcomes in euthyroid women undergoing ART: A meta-analysis

Thyroid autoimmunity (TAI) triggered by genetic and epigenetic variation occurs mostly in women of reproductive age. TAI is described mainly by positivity of anti-thyroid peroxidase antibody (TPO-Ab) and/or thyroglobulin antibody (TG-Ab). TPO-Ab, but not TG-Ab, was suggested to be associated with pregnancy outcome in euthyroid women undergoing assisted reproductive technology (ART), but their results are conflicting. This meta-analysis was performed to decide whether the presence of TPO-Ab-in a concentration dependent manner-correlates with the success of ART. A systematic literature search was performed in the PubMed, Web of Science, and EMBASE databases for relevant articles published from January 1999 to April 2022, and these studies focused on the effect of TAI on pregnancy outcomes of women who underwent in vitro fertilization, intracytoplasmic sperm injection and intrauterine insemination and met the inclusion criteria: (i) the studies were prospective or retrospective study; (ii) all patients undergoing ART were tested for thyroid-related antibodies; (iii) the assessed ART outcomes included miscarriage rate (MR) or delivery rate (DR). The exclusion criteria were: (i) female congenital uterine malformation, chromosomal diseases and other infectious diseases; (ii) overt hypothyroidism or pre-existing thyroid disease; (iii) thrombus tendency. We divided the included patients into three groups according to the TPO-Ab threshold they defined: (i) TPO-Ab (-), threshold <34 IU/mL; (ii) TPO-Ab-34, threshold >34 IU/mL; (iii) TPO-Ab-100, threshold >100 IU/mL. We then extracted necessary relevant data, including MR and DR. Egger's test was used to evaluate the risk of publication bias. This meta-analysis included a total of 7 literatures involving 7466 patients with TAI (-) and 965 patients with TAI (+) and revealed that there was no significant difference between group TPO-Ab-34 and group TPO-Ab (-) in MR [risk ratio (RR): 0.61 (0.35, 1.08), p = 0.09] and DR [RR: 0.97 (0.83, 1.13), p = 0.69]. By contrast, compared to TPO-Ab (-) group, TPO-Ab-100 patients showed markedly higher MR [RR: 2.12 (1.52, 2.96), p = 0.0046], and lower DR [RR: 0.66 (0.49, 0.88), p < 0.0001] with high degree of statistical significance. This meta-analysis suggests that, for euthyroid patients, high level of TPO-Ab (>100 IU/mL) could adversely influence the pregnancy outcome of ART.

Impact of Thyroid Autoimmunity on Assisted Reproductive Technology Outcomes and Ovarian Reserve Markers: An Updated Systematic Review and Meta-Analysis

Background: Thyroid autoimmunity (TAI) has a high prevalence among women of reproductive age. Investigating its possible impact on ovarian function and fertility is, thus, of utmost relevance. The aim of this systematic review and meta-analysis was to elucidate the effect of TAI on both assisted reproductive technology (ART) outcomes and ovarian reserve. Methods: This systematic review and meta-analysis was restricted to two groups of research articles investigating the association between TAI and: (1) autologous ART outcomes (i.e., fertilization rate [FR], implantation rate, clinical pregnancy rate [CPR], miscarriage rate, and live birth rate), (2) markers of ovarian reserve (i.e., anti-Müllerian hormone, basal follicle stimulating hormone, antral follicle count, and number of oocytes retrieved). Studies including women affected by overt hypo/hyperthyroidism were excluded. Relevant studies were identified by a systematic search in PubMed, MEDLINE, ClinicalTrials.gov, Embase, and Scopus, from database inception to May 1, 2022. Results: From a total of 432 identified publications, 22 studies were included in Group 1 and 26 studies in Group 2. The presence of TAI was associated with a higher risk of miscarriage (7606 participants, odds ratio [OR] 1.52, confidence interval [CI 1.14-2.01], p = 0.004, I² = 53%), lower chance of embryo implantation (7118 participants, OR 0.72, [CI 0.59-0.88], p = 0.001, I² = 36%), and live birth (11417 participants, OR 0.73, [CI 0.56-0.94], p = 0.02, I² = 71%). These associations were no longer observed in a subgroup analysis of patients who exclusively underwent intracytoplasmic sperm injection (ICSI). The FR and CPR as well as the mean values of surrogate markers of oocyte quantity appeared not to be affected by TAI. Conclusions: This data synthesis suggest a higher risk of adverse ART outcomes in women with positive TAI. However, the reliability of these findings is hampered by the relatively low quality of the evidence and significant heterogeneity in many of the meta-analyses. The possible protective effect of ICSI is promising but should be confirmed in controlled prospective clinical trials. PROSPERO Registration ID: CRD42021236529.

Evaluation of the relationship between serum TSH levels and pregnancy outcomes of IVF/ICSI patients in follicular phase long-acting long protocol

ObjectiveTo investigate whether TSH levels are associated with the pregnancy outcomes of patients in the follicular phase long-acting long protocol of IVF/ICSI.MethodsThis was a single-central, retrospective study which was conducted in the Reproductive Medicine Center, Renmin Hospital of Wuhan University from February 2019 to April 2021. A total number of 773 patients underwent the follicular phase long-acting long protocol during in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment were divided into Group A (0.5 mIU/L ≤ TSH ≤2.5 mIU/L, n = 463) and Group B (2.5 mIU/L < TSH≤ 4.5 mIU/L, n = 310) according to their serum TSH levels. The clinical data and pregnancy outcomes were compared between the two groups. The possible relationship between TSH levels and pregnancy outcomes in people who performed follicular phase long-acting long protocol was investigated.ResultsThe proportion of patients with infertility due to ovulation disorders was significantly greater in Group B than in Group A (p = 0.036). The duration of Gn of Group B was significantly longer than that of Group A (p = 0.001). The Gn dose of Group B was significantly larger than that of Group A (p = 0.002). Besides, the implantation rate and miscarriage rate of embryos transferred on D3 were significantly higher in Group B than that of Group A (p = 0.033, p = 0.026 respectively).ConclusionsThe higher implantation and miscarriage rates of D3 of IVF/ICSI in the follicular phase long-acting long protocol may be related to higher serum TSH levels.

Effect of thyroid function on assisted reproduction outcomes in euthyroid infertile women: A single center retrospective data analysis and a systematic review and meta-analysis

BACKGROUND

The influence of thyroid-stimulating hormone (TSH) on gestational outcomes have been studied and checked whether differing TSH levels are relevant on human reproduction outcomes. International guidelines recommend TSH values <2.5 mIU/L in women trying to conceive, since values above this level are related to a higher frequency of adverse reproductive outcomes. This study aimed to evaluate whether TSH values correlate with different gestational outcomes in euthyroid infertile women without autoimmune thyroid disease.

METHODS

A retrospective cohort study was conducted involving 256 women who underwent in vitro fertilization (IVF) treatment. The participants were divided into two groups: TSH 0.5-2.49 mIU/L (n=211) and TSH 2.5-4.5 mIU/L (n=45). The clinical data, hormonal profiles and reproductive outcomes were compared between groups. Additionally, a systematic review with meta-analysis following the PRISMA protocol was carried out in PubMed/MEDLINE, EMBASE, and SciELO, with no time or language restrictions, for articles comparing TSH groups named "low TSH" (<2,5 mIU/L) and "high TSH" (≥2.5 mIU/L). A meta-analysis of proportions was performed with pooled estimates expressed as relative risk (RR) of events and a random effects model.

RESULTS

Age, BMI, free thyroxine levels (FT4) hormonal profile and IVF outcomes were not different between groups, neither gestational outcomes (p=0.982). Also, no difference was observed when the TSH and FT4 levels were compared between patients with positive or negative gestational outcomes (p=0.27 and p=0.376). Regarding the systematic review with meta-analysis, 17 studies from 2006 to 2022 were included, and added by this original retrospective research comprising 13.247 women undergoing IVF. When comparing the proportions of clinical pregnancy between the TSH groups, no significant difference was found (RR 0.93, 95% CI 0.80-1.08), with high between studies heterogeneity (I²: 87%; τ²: 0.0544; p<0.01). The number of deliveries was not significantly different between groups, despite a trend towards higher frequency in the high-TSH group (RR 0.96, 95% CI 0.90-1.02).

CONCLUSION

Variation in TSH levels within the normal range was not associated with pregnancy and delivery rates in women, without autoimmune thyroid disease, who underwent IVF treatment.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD 42022306967.

The Impact of High-Normal TSH Levels on Reproductive Outcomes in Women Undergoing ART Treatment: a Systematic Review and Meta-analysis

The role of high-normal thyroid-stimulating hormone levels has been of great concern recently. However, the conclusions of different studies are inconsistent. To assess whether high-normal conditions have an impact on reproductive and obstetric outcomes in euthyroid women undergoing ART treatment, a systematic review and meta-analysis was performed. Eligible studies published up to December 30, 2020, were searched from the PubMed, EMBASE, COCHRANE, and CNKI databases. Quality assessment of the included studies, data extraction, and synthesis were performed separately. RevMan 5.2 was used to carry out the meta-analysis. A total of 23 studies that included 25,143 patients were included. We observed similar clinical pregnancy rates (RR = 1.01, 95% CI: 0.99-1.05), miscarriage rates (RR = 0.95, 95% CI: 0.84-1.08), live birth rates (RR = 1.04, 95% CI: 0.99-1.09), birth weights (SMD = 0.07, 95% CI: -0.02 to 0.16), and gestational ages (SMD = 0.07, 95% CI: -0.02 to 0.16) between the high-normal TSH group and low TSH group. Subgroup analysis showed similar results. High-normal TSH levels were associated with similar clinical pregnancy rates, live birth rates, and miscarriage rates to those of women with low TSH levels. The results suggested that preconceptional TSH levels, regardless of potentially being affected by the controlled ovarian stimulation process, had little impact on reproductive and obstetric outcomes and should not be of great concern.

Impact of Thyroid Autoimmunity on In Vitro Fertilization/Intracytoplasmic Sperm Injection Outcomes and Fetal Weight

Several studies have reported the association between thyroid autoimmunity (TAI) and in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcomes. However, the findings remain controversial. We performed a large-scale retrospective cohort study to verify the effect of the presence of thyroid antibodies on IVF/ICSI outcomes and fetal growth and to evaluate the association between the types and titers of thyroid antibodies and adverse IVF/ICSI outcomes. A total of 16481 patients with infertility were referred to the Reproductive Center of Peking University Third Hospital for their first IVF/ICSI treatment between January 2018 and June 2019.Patients who sought IVF/ICSI treatment due to tubal or male factors infertility and who achieved fresh embryo transfer were included in our study. Finally, 778 patients with thyroid antibody positivity were selected as the TAI group, and 778 age-matched patients were included in the control group. The number of oocytes retrieved and high-graded embryos and the rates of clinical pregnancy, miscarriage, live birth, and preterm delivery were compared between the TAI and control groups. In addition, subgroup analysis was performed to demonstrate whether different types and titers of thyroid antibodies had different effects on IVF/ICSI outcomes. After adjusting for thyroid function, anti-Müllerian hormone levels, basal follicle stimulating hormone levels, basal estradiol levels and antral follicle count, the number of oocytes retrieved in the TAI group was significantly lower than that in the control group. No significant differences were observed between the two groups in the rates of clinical pregnancy, miscarriage, preterm delivery, live birth, and birth weight in singletons; however, the birth weight in twin pregnancy was significantly lower in the TAI group than in the control group. Subgroup analysis showed no association between the types or titers of thyroid antibodies and adverse IVF/ICSI outcomes. In conclusion, the presence of TAI in patients with infertility did not impair embryo quality or affect pregnancy outcomes, including clinical pregnancy, miscarriage, preterm delivery, and live birth. However, it decreased the number of oocytes retrieved and birth weight in twin pregnancy.

Risk factors of subclinical hypothyroidism and the potential contribution to miscarriage: A review

BACKGROUND

There is no clear cutoff value for thyroid-stimulating hormone (TSH) level that defines subclinical hypothyroidism (SCH). Moreover, TSH levels can be affected by numerous factors. Although mild SCH has been implicated in miscarriage, the relationship between TSH levels and miscarriage remains unelucidated.

METHODS

We reviewed nine known risk factors affecting TSH levels and 28 studies investigating the potential association between mild SCH and miscarriage, examining whether these factors were considered.

MAIN FINDINGS

Among 28 studies that examined whether mild SCH (TSH > 2.5 mIU/L) contributed to miscarriage, thyroid antibodies were measured in only 15. TSH measurement methods were described in 18 studies. Although the iodinated contrast medium used in hysterosalpingography (HSG) is stored in the body for a long time and is a risk factor for mild SCH, only one study described its potential impact on TSH levels. Nine studies, which concluded that mild SCH contributed to miscarriage, had thyroid status evaluated only after the onset of pregnancy, but not before.

CONCLUSION

TSH levels can be significantly affected by patient demographics and health history, country of origin, and fertility treatment. It is important to consider these factors while evaluating mild SCH. It remains unclear how mild SCH contributes to miscarriage.

The impact of thyroid autoantibodies on the cycle outcome and embryo quality in women undergoing intracytoplasmic sperm injection

Background

The influence of thyroid autoimmunity in in–vitro fertilization/intracytoplasmic sperm injection (ICSI) cycles is still a controversial issue. Although some women are euthyroid, some studies found thyroid dysfunction and thyroid autoimmunity increased the incidence of infertility. We aimed to evaluate the impact of anti-thyroid antibodies on the cycle parameters, embryo quality, and pregnancy outcomes in women who underwent ICSI cycles.

Results

Fertilization rate was significantly higher in anti-thyroid antibody-negative patients than in anti-thyroid antibody-positive patients (97.1 ± 10.5 vs. 91.5 ± 19.8, respectively, p = 0.003). Clinical pregnancy, miscarriage, and ongoing pregnancy rates were not different among study groups. The presence of top-quality embryo was lower in anti-thyroid antibody-positive patients but it did not reach any statistical significance (56.5% vs. 67.8%, p = 0.09). In the subgroup analysis, there were no significant differences except for the miscarriage rate according to the TSH threshold.

Conclusion

The clinical pregnancy and ongoing pregnancy were not affected by the positivity of anti-thyroid antibodies. We showed that thyroid autoimmunity may have an impact on fertilization rate and embryo quality in patients undergoing ICSI cycles. Miscarriage rate also increases with thyroid autoimmunity and TSH levels above 2.5 μIU/L.

Association between TSH Level and Pregnancy Outcomes in Euthyroid Women Undergoing IVF/ICSI: A Retrospective Study and Meta-analysis

The aim of this study was to determine the association between thyroid-stimulating hormone (TSH) level and pregnancy outcomes in euthyroid women undergoing in vitro fertilization (IVF)/intra-cytoplasmic sperm injection (ICSI). A total of 1185 women were enrolled in the retrospective study, and 12 studies with a total of 6624 women were included in the meta-analysis (including the data of the present retrospective study). Participants in the retrospective study were divided into two groups in terms of their serum TSH levels: TSH ≤2.5 mIU/L group (n=830) and TSH >2.5 mIU/L group (n=355). They were monitored for the status of clinical pregnancy or miscarriage. In the TSH ≤2.5 mIU/L group, 441 (53.1%) women achieved clinical pregnancy, while 48 (5.8%) had early pregnancy loss and 12 (1.4%) had ectopic pregnancy. In the TSH >2.5 mIU/L group, 175 (49.3%) women achieved clinical pregnancy, while 21 (5.9%) had early pregnancy loss and 3 (0.8%) had ectopic pregnancy. No significant differences were observed between the two groups in pregnancy outcomes (P=0.126, P=0.512, P=0.297). The meta-analysis also revealed no significant difference in the clinical pregnancy rate and the miscarriage rate between women with serum TSH ≤2.5 mIU/L and those with serum TSH >2.5 mIU/L. In conclusion, high TSH levels (TSH level >2.5 mIU/L) did not affect clinical pregnancy rate or increase miscarriage rate in euthyroid women undergoing IVF/ICSI.

The Impact of Autoantibodies on IVF Treatment and Outcome: A Systematic Review

The role of autoantibodies in in vitro fertilization (IVF) has been discussed for almost three decades. Nonetheless, studies are still scarce and widely controversial. The aim of this study is to provide a comprehensive systematic review on the possible complications associated to autoantibodies (AA) impeding the chances of a successful IVF cycle. An Embase, PubMed/Medline and Cochrane Central Database search was performed on 1 December 2018, from 2006 until that date. From the 598 articles yielded in the search only 44 relevant articles ultimately fulfilled the inclusion criteria and were qualitatively analyzed. Five subsets of results were identified, namely, thyroid related AA, anti-phospholipid antibodies, anti-nuclear antibodies, AA affecting the reproductive system and AA related to celiac disease. It may be implied that the majority of auto-antibodies exert a statistically significant effect on miscarriage rates, whereas the effects on clinical pregnancy and live birth rates differ according to the type of auto-antibodies. While significant research is performed in the field, the quality of evidence provided is still low. The conduction of well-designed prospective cohort studies is an absolute necessity in order to define the impact of the different types of autoantibodies on IVF outcome.

Meta-analysis of ART outcomes in women with different preconception TSH levels

BACKGROUND

To assess whether elevated thyroid-stimulating hormone (TSH) levels before conception can predict poor outcomes of assisted reproductive technology (ART).

METHODS

Prior to July 2018, we searched the PubMed, EMBASE, COCHRANE, Google Scholar, and CNKI databases for studies. Retrospective or prospective reports that compared ART results in patients with subclinical hypothyroidism (SCH) with normal thyroid function were selected. Two reviewers separately reviewed each potential article for qualification, analyzed the quality of the studies according to the Newcastle-Ottawa scale, and extracted the data. The PRISMA guidelines were adopted.

RESULTS

We selected a total of 18 publications that included 14,846 participants for this meta-analysis. When the TSH cut-off value for SCH was set at 2.5 mIU/L, no significant differences were observed in ART-related outcomes between SCH patients and normal women. The evaluated outcomes included the live birth rate (LBR) (OR: 0.93; 95% CI (0.77,1.12), P = 0.43), clinical pregnancy rate (CPR) (OR:1.02; 95% CI (0.90,1.17); P = 0.74), pregnancy rate (PR) (OR: 1.00; 95% CI (0.89,1.12); P = 0.99), and miscarriage rate (MR) (OR:1.24; 95% CI (0.85, 1.80); P = 0.26). Furthermore, when a higher TSH level was used as the cut-off value to diagnose SCH (i.e., 3.5-5 mIU/L), a significant difference was found in the MR (OR: 1.91; 95% CI (1.09, 3.35); P = 0.02) between the two groups of ART-treated women. However, when a broader cut-off value was used to define SCH, no significant differences were observed in the LBR (OR: 0.72; 95% CI (0.47,1.11); P = 0.14), CPR (OR: 0.82; 95% CI (0.66,1.00); P = 0.052), or PR (OR: 1.07; 95% CI (0.72,1.60); P = 0.74) between the two groups of ART-treated women.

CONCLUSION

No difference was observed in ART outcomes when a TSH cut-off value of 2.5 mIU/L was used. However, when a broader TSH cut-off value was used, preconception SCH resulted in a higher miscarriage rate than in normal women.

In vitro fertilization/intracytoplasmic insemination and thyroid function: reviewing the evidence

Recent findings, that specific G protein-coupled TSH receptors (TSHR) and the nuclear thyroid hormone receptors (THRs) are widely expressed in reproductive tissues, reveal the close links between hypothalamus-pituitary-thyroid and hypothalamus-pituitary-gonadal axes. It has been suggested that thyroid function as well as thyroid autoimmunity (TAI) have an impact on Assisted Reproduction Technology (ART) reproductive outcome. Lately, it became evident that ovarian stimulation (OS) may also have an impact on thyroid function. This narrative review describes the mutual interaction between thyroid function and OS, by reviewing the current evidence, assessing the pathophysiological links and arriving at practical recommendations.

'Does levothyroxine improve pregnancy outcomes in euthyroid women with thyroid autoimmunity undergoing assisted reproductive technology?'

Evidence on the treatment of euthyroid infertile women and thyroid autoimmunity with thyroid hormone is scare, and therefore the recent study by Wang et al. is a welcome addition to it. Based on their results, thyroid hormone seems not to be indicated to decrease the miscarriage rate in that particular group of infertile women. This comment is meant to put the study results into perspective with the available evidence and the current guidelines, and to highlight its strengths and weaknesses.

Thyroid autoimmunity and intracytoplasmic sperm injection outcome: a systematic review and meta-analysis

BACKGROUND

Since 2010, three meta-analyses have been published on the impact of thyroid autoimmunity (TAI) on pregnancy outcomes in infertile women treated with assisted reproductive technology (ART). The initially observed high risk of miscarriage became very low in the most recent meta-analysis published in 2016.

OBJECTIVE

To investigate whether the lower risk of miscarriage in the latest meta-analysis was associated with the increased use of intracytoplasmic sperm injection (ICSI) in recent studies.

DATA SOURCE

MEDLINE was searched from January, 1990, to May, 2017.

STUDY SELECTION

Data from case-control and cohort studies, on ART (IVF/ICSI) pregnancy outcomes in women with and without TAI. Only studies were included in which women were treated with ICSI.

DATA EXTRACTION AND SYNTHESIS

Four studies were retained including 1855 ICSI cycles (290 with and 1565 without TAI). In women with a clinical pregnancy (114 ICSI cycles with TAI and 651 without), there was no difference in miscarriage or live birth rates: respective combined OR 0.95 (95% CI, 0.48 to 1.87) and 1.12 (95% CI, 0.62 to 2.03). There was no difference in age in women with and without TAI: combined mean difference of 0.13 years (95% CI, -0.51 to 0.76), but serum TSH was higher in women with TAI: combined mean difference of 0.20 mIU/L (95% CI, 0.07 to 0.33).

CONCLUSION

Infertile women with TAI treated with ICSI had no increased risk of a first trimester miscarriage compared with women without TAI.

A post-publication analysis of the idealized upper reference value of 2.5 mIU/L for TSH: Time to support the thyroid axis with magnesium and iron especially in the setting of reproduction medicine

Laboratory medicine approaches the evaluation of thyroid function mostly through the single determination of the blood level of thyroid stimulating hormone (TSH). Some authors have suggested an upper reference value for TSH of 2.5 mIU/L. This suggestion has not been confirmed by recent clinical studies. These studies have delivered a clinically valid reference range going from 0.3 to 3.5 mIU/L. These values are valid for both for the general population as well as in the setting of fertility and pregnancy. Current biochemical evidence about the elements required to maintain thyroid function shows that these not only include dietary iodine but also magnesium, iron, selenium and coenzyme Q10. Iron is important for the synthesis of thyroid peroxidase; magnesium-ATP contributes to the active process of iodine uptake; iodine has to be sufficiently present in the diet; selenium acts through selenoproteins to protect the thyroid cell during hormone synthesis and in deiodination of thyroxine; coenzyme Q10 influences thyroid vascularity. As a consequence, good clinical practice requires additional biochemical information on the blood levels of magnesium, selenium, coenzyme Q10 as well as iron status. Since these elements are also important for the maintenance of reproductive function, we postulate that they constitute the connecting link between both endocrine systems.

Effect of thyroid autoimmunity per se on assisted reproduction treatment outcomes: A meta-analysis

OBJECTIVE

Thyroid autoimmunity (TA) is the most prevalent autoimmune disease in women of reproductive age and is often accompanied by subclinical hypothyroidism (SCH). Both TA and SCH have been associated with adverse pregnancy outcomes, but their relative influence is unclear. Therefore, we carried out a meta-analysis to evaluate the sole effect of TA on pregnancy outcomes in euthyroid women undergoing assisted reproductive technology.

MATERIALS AND METHODS

Literature searches were conducted on Pubmed, EMBASE, and the Cochrane Controlled Trials Register Database from inception to May 2014.

RESULTS

In euthyroid women whose SCH status is unknown, those with positive antithyroid antibodies (ATA) had a higher miscarriage rate [pooled relative risk (RR) = 1.638; 95% confidence interval (CI), 1.228-2.185] and a lower delivery rate (pooled RR = 0.856; 95% CI, 0.759-0.965) than those with negative ATA. Clinical pregnancy rates were similar between groups. However, clinical pregnancy rate, miscarriage rate, and delivery rate were all comparable between ATA-positive and ATA-negative euthyroid women without SCH.

CONCLUSION

TA per se does not impair assisted reproductive treatment outcomes in women without SCH.

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.

The impact of the presence of antithyroid antibodies on pregnancy outcome following intracytoplasmatic sperm injection-ICSI and embryo transfer in women with normal thyreotropine levels

PURPOSE

The aim of our study was to investigate the impact of anti-thyroid peroxidase antibodies (Anti-TPO) on pregnancy outcome following the in vitro fertilization and embryo transfer (IVF-ET) in general groups and in subgroups divided according to AMH level and age.

METHODS

A total of 114 patients positive for anti-thyroid peroxidase antibodies (Anti-TPO+ group) and 495 infertile women negative for anti-thyroid peroxidase antibodies (Anti-TPO- group) undergoing IVF with ICSI from April 2010 to April 2012 were analyzed retrospectively.

RESULTS

There were no significant differences in age, BMI, basal FSH, LH, AMH levels and duration of infertility between the two main groups. No significant differences in terms of the days of ovarian stimulation, estradiol level in day 8, total gonadotropin dose, number of oocytes retrieved, available embryos and blastocysts, number of embryos transferred nor in rates of fertilization, implantation, clinical pregnancy, live birth and abortion rate between two main groups were found. The only statistically significant difference among the groups with different anti-TPO antibodies levels was found in basal FSH concentration and BMI. Among the clinical outcomes of IVF with respect to the different anti-TPO levels, the only significant difference was found for the number of oocytes retrieved. Analysis of the baseline parameters in relationship to age categories and AMH levels found significant differences between women positive and negative for thyroid antibodies with respect to basal FSH and LH levels for women >37 years and for basal FSH in AMH <0.6 subgroup.

CONCLUSIONS

The present study reveals that patients with anti-TPO antibodies showed no significant differences in fertilization, implantation, pregnancy rates, live birth rates and no higher risk for miscarriage following IVF-ET when compared with those negative for anti-thyroid antibodies.

Investigating the optimal preconception TSH range for patients undergoing IVF when controlling for embryo quality

PURPOSE

The ideal thyroid-stimulating hormone (TSH) range for infertile women attempting conception has not been determined. Current recommendations include optimizing the preconception TSH value to ≤2.5 mIU/L, which is the established goal for pregnant women. The aim of this study was to determine if there is a distinct range of TSH ≤2.5 mIU/L for infertile women undergoing in vitro fertilization (IVF) that improves reproductive outcomes.

METHODS

One thousand five hundred ninety-nine euploid blastocyst transfer cycles were evaluated in which TSH measurements were obtained 8 days after embryo transfer. Only euploid embryo transfers were included in an effort to control for embryo quality. Patients were separated into TSH groups utilizing 0.5 mIU/L increments. Implantation, live birth, and miscarriage rates among the TSH groups were compared. Outcomes for individuals on thyroid hormone supplementation and those not requiring supplementation were evaluated.

RESULTS

There was no difference in implantation (p = 0.56), live birth (p = 0.36), or miscarriage rates (p = 0.10) between TSH groups. Receiver operating characteristic (ROC) curves for implantation, live birth, and miscarriage approached the line of no discrimination, signifying that there is no value of TSH within the recommended range for pregnancy (≤2.5 mIU/L) that predicts IVF outcomes better than other values in this range. Live birth rates for patients requiring thyroid hormone supplementation and those not on medication were similar (p = 0.86).

CONCLUSIONS

The recommended TSH range for pregnancy (≤2.5 mIU/L) may be applied to infertile patients attempting conception without a need for further adjustment.

The role of magnesium and thyroid function in early pregnancy after in-vitro fertilization (IVF): New aspects in endocrine physiology

Background

The initiation of a pregnancy is a process that requires adequate energetic support. Recent observations at our Institution suggest a central role of magnesium in this situation. The aim of this study was to evaluate magnesium, zinc, selenium and thyroid function as well as anti-Müllerian hormone in early pregnancy following in-vitro fertilization as compared to spontaneous successful pregnancies.

Results

A successful outcome of pregnancy after IVF treatment was associated with 2 parameters: higher levels of anti-Müllerian hormone as well as higher levels of magnesium in the pre-stimulation blood sample. These two parameters, however, showed no correlation. Spontaneous pregnancies as well as pregnancies after IVF show a fall of magnesium levels at 2–3 weeks of gestation. This drop of magnesium concentration is larger following IVF as compared to spontaneous pregnancies. Parallel to these changes TSH levels showed an increase in early IVF-pregnancy. At this time point we also observed a positive correlation between fT4 and TSH. This was not observed in spontaneous pregnancies. Thyroid antibodies showed no correlation to outcomes.

Conclusions

In connection with the initiation of pregnancy following ovarian stimulation dynamic changes of magnesium and TSH levels can be observed. A positive correlation was found between fT4 and TSH in IVF pregnancies. In spontaneous pregnancies smaller increases of TSH levels are related to higher magnesium levels.

General significance

We propose that magnesium plays a role in early pregnancy as well as in pregnancy success independently from anti-Müllerian hormone. Neither thyroid hormones nor thyroid antibodies were related to outcome.

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Lack of correlation of thyroid function parameters to IVF outcome

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Significant drop of magnesium levels in early pregnancy after IVF

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Positive correlation between fT4 and TSH levels in early pregnancy following IVF

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Higher anti-Müllerian hormone levels are associated to successful IVF pregnancies.

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Higher magnesium levels are associated to successful IVF pregnancies.