{"paper_id":"74e5811e-85af-414f-964f-3e9ba54ed7c3","body_text":"Thyroid disorders are one of the most common endocrinological diseases affecting\nwomen of reproductive age ( Negro & Mestman,\n2011 ;  Krassas  et al .,\n2010 ;  Sarac & Koc, 2018 ). They\nare associated with adverse reproductive outcomes such as spontaneous abortion and\ninfertility ( Krassas  et al .,\n2010 ;  Kalem  et al .,\n2016 ;  Liu  et al .,\n2005 ). Hypothyroidism is responsible for harmful effects on fetal health,\nthe guidelines suggest that TSH (thyroid stimulating hormone) levels should be\n<2.5 mIU/L in pregnant or first trimester pregnant women ( Burman, 2009 ;  Garber  et\nal ., 2012 ). The 2012 guidelines of the American Thyroid\nAssociation and the American Society of Clinical Endocrinologists recommend limiting\nserum TSH to 2.5 mIU/L in euthyroid patients planning to become pregnant ( Garber  et al ., 2012 ). However,\nin 2017 the American Society of Thyroid Guidelines recommended the upper reference\nlimit of TSH to 4.0 mIU/L ( Alexander  et\nal ., 2017 ). There is no clear consensus on the efficacy of\nan upper value for TSH and the effects on fertility outcomes ( Miko  et al.,  2017 ).\nChronic autoimmune thyroiditis (named Hashimoto thyroiditis) (HT), is the most common\nendocrinopathy in premenopausal women in developed countries ( Friedrich  et al ., 2008 ). All over the world,\niodine deficiency is still the most common cause of thyroid dysfunction ( Hayashi  et al ., 1986 ). Various\nstudies have shown that HT is associated with various gynecological problems,\nrecurrent miscarriage, unexplained infertility, and  in vitro \nfertilization failure ( Dendrinos  et\nal ., 2000 ;  Poppe  et\nal ., 2007 ;  van den Boogaard\n et al ., 2011 ;  Aydın  et al ., 2008 ).\nThere is a negative association between maternal thyroid dysfunction and low birth\nweight, preterm birth, preeclampsia and decreased intelligence ( De Groot  et al ., 2012 ).\nSubclinical hypothyroidism without thyroid autoantibodies seems to be related to the\nproblems mentioned above ( Negro  et\nal ., 2010 ;  Benhadi  et\nal ., 2009 ). Therefore, hypothyroidism treatment during\npregnancy is essential. Recommendations for the treatment of subclinical\nhypothyroidism before and during pregnancy also differ ( Vila  et al ., 2014 ).\nIntrauterine insemination (IUI) is widely used to treat infertility, and it is\nconsidered a non-invasive and less expensive treatment when compared to assisted\nreproduction techniques (ART) such as  in vitro  fertilization (IVF)\n( Dilbaz  et al.,  2011 ).\nThe clinical pregnancy rates differ between indications in 8-20% per cycle ( Merviel  et al ., 2014 ; Dilbaz\n et al ., 2011). Fertility treatment outcome in the presence of\nthyroid problems is challenging ( Practice Committee\nof the American Society for Reproductive, 2015 ;  Tan  et al ., 2014 ;  Tuncay  et al ., 2018 ).\nIn this study, we aimed to evaluate a possible association between subclinical\nhypothyroidism and thyroid autoantibodies with clinical pregnancy rates after\nintrauterine insemination in euthyroid women.\n\nWe recruited 497 women who applied to the reproductive endocrinology and\ninfertility clinics of the Zekai Tahir Burak Women's Health Education and\nResearch Hospital from October 2015 to June 2017 in this prospective cohort\nstudy. The study was approved by the Local Ethics Committee of the institution\n(05.27.2015 #20), and the universal principles of the Declaration of Helsinki\nwere applied ( World Medical Association,\n2013 ). We excluded those with tubal factor infertility, male\ninfertility, endometriosis, and systemic disorders such as overt diabetes\nmellitus, cardiac pathologies and known thyroid diseases (medications such as\nlevothyroxine or anti-thyroid drugs). Semen samples were obtained by\nmasturbation after 2-3 days of sexual abstinence. Sperm preparation was\nundertaken using the swim-up technique and stored at room temperature until the\ntime of insemination. IUI was performed using a soft IUI catheter. Semen\nparameters were analyzed according to the WHO 2010 criteria ( Cooper  et al ., 2010 ). All\npatients received clomiphene citrate treatment (50-100 mg/day)\n(Klomen @ , Kocak Farma, Istanbul, Turkey) orally or 37.5-150 IU of\npure FSH or human menopausal gonadotropin (hMG) (Gonal-F @ , Merck\nSereno/ Menogon @ , Ferring Pharmaceuticals Istanbul, Turkey),\nrespectively starting on 3-5 cycle days of menstruation and lasting until 7-9\ncycle days of menstruation for ovulation induction. The drug dosage was\nindividualized according to patient response and/or the data from the previous\ncycles. We performed serial transvaginal ultrasonography (TVUS) examinations. We\nadministered a dose of 10,000 IU of urinary HCG or 250 mg of recombinant HCG\n(Pregnyl @ , Organon, Istanbul, Turkey, respectively) when at least\none follicle of ≥18 mm was seen upon transvaginal ultrasonography. To\nprevent multiple pregnancies, we included only cycles with mono and\nbi-follicular growth (>18 mm) in the analysis.\nWe evaluated the demographic features, infertility types, infertility duration,\nendometrial thickness on HCG day, basal hormonal parameters (FSH, E2), thyroid\nfunction tests [free tri-iodothyronine (fT3) and free thyroxine (fT4) and TSH],\nthyroid antibodies [antithyroid peroxidase (anti-TPO) and antithyroglobulin\n(anti-TG) antibodies] and clinical pregnancy rates of the patients. We ran a\nqualitative serum β-HCG test 14 days after insemination if menstruation\nhad not started. Clinical pregnancy was defined as the presence of a gestational\nsac with accompanying fetal heartbeat by ultrasound at least 4 weeks after\nIUI.\nBlood samples were taken from the participants' antecubital veins. All serum\nparameters included in this analysis were obtained on the 3rd to the 5th day of\nthe menstrual cycle with IUI. In our department, the normal range for TSH is\n0.34-5.6µIU/ml; for fT3 it is 2.5-3.9pg/ml; for fT4 it is 0.61-1.12ng/dl;\n0-9IU/ml for anti-TPO; and 0-4IU/ml for anti-TG. These normal ranges were\ncalculated by the laboratory and all examined serum parameters were determined\nin the ISO-certified central laboratory of the Dr. Zekai Tahir Burak Women's\nHealth Care University of Health Sciences, Education and Research Hospital,\nAnkara, TURKEY, using commercially available assays using the Elecsys\nelectrochemiluminescence immunoassays on a Cobas 6000 immunoanalyzer (Roche\nDiagnostics, Mannheim, Germany). The inter and intra assay CVs were <2% and\n<6.5% for TSH, ≤2% and <5% for fT4, ≤2% and <5% for fT3,\n<5% and ≤7% for anti-TPO, <2% and ≤5% for anti-TG. The TSH\nmeasuring range was 0.005-100 µIU/mL; for fT3 it was 0.3-10 nmol/L; for\nfT4 it was 0.101-7.77 ng/dL; for anti-TPO it was 5-600 IU/ml; for anti-TG it was\n10-4000 IU/ml.\nWe used the statistical Package for the Social Sciences, version 23.0 (SPSS Inc.,\nChicago, IL) for the statistical analysis. The sample size calculation for the\nentire study population, a two-sample comparison with a 5% level of significance\n(alpha) and a power of 0.80 with an allocation ratio of 3:1, gave a study\npopulation of 315  vs.  104 women in each group. Sample size\ncalculations were performed using the G*Power v3.1.5 general power analysis\nprogram ( Faul  et al .,\n2007 ). For quantitative data, we used mean values and standard\ndeviations, whereas for quantitative data we used numbers and percentages. We\nused the Kolmogorov-Smirnov and Shapiro-Wilk tests to assess the normal\ndistribution of the univariate variables. In order to analyze the variables that\ndid not have normal distribution we used non-parametric methods. Non-parametric\nvariables between groups were compared through the Mann-Whitney U test. For\ncategorical variables we used the Fisher's exact or the Pearson Chi-Square test,\nwhere appropriate. We ran an ROC curve analysis to determine a cut-off value for\npregnancy prediction.  p  values less than 0.05 indicated\nstatistical significance. The  p- value presented in our\nstatistical analysis are for two-tailed tests.\n\nThe area under the ROC curve revealed that no cut-off value of TSH can predict\npregnancy in intrauterine insemination cycles (the area under the ROC curve was\n0.495 (%95 CI: 0.424-0.566) ( p -value=0.887). Therefore, the\npatients were divided into two groups as TSH values between 0.35-2.49mIU/L (group 1,\nn=387) and 2.52-4.88 mIU/L (group 2, n=110). The groups were statistically\ncomparable in terms of the variables mentioned.\nDemographic features of the subjects are shown in  Table 1 . Of these, 387 women (77.2%) had TSH values between 0.35-2.49\nmIU/L (control group), and 110 women (22.8%) had TSH values between 2.52-4.88 mIU/L\n(study group). There were no statistically significant differences between the\ngroups in terms of age, BMI, infertility duration, infertility type\n(primer/seconder), ovulation induction protocol and clinical pregnancy rates\n( p >0.05). The clinical pregnancy rate was 15.2% in the\nControl Group and 17.3% in the study group ( p =0.656). There was no\nstatistically significant difference between the groups in terms of FSH, E2 and\nendometrial thickness on the ovulation trigger day ( Table 2 ).\nComparison of the subjects' demographic features\nFisher’s exact\nMann Whitney U\nLaboratory parameters\nFisher’s exact\nMann Whitney U\nAnti-TPO positivity was present in 35%  vs.  29.2% of patients in the\nStudy and Control groups, respectively ( p =0.531); while anti-TG\npositivity was present in 42.1%  vs.  29% in the Study and Control\ngroups, respectively ( p =0.285) ( Table 2 ). There was no statistically significant difference for clinical\npregnancy rates between the groups in terms of antithyroid antibody positivity\n( Figures 1  and  2 ). No statistically significant difference between the groups\nwas seen in terms of fT3 and fT4 results ( p =0.54;\n p =0.559, respectively) ( Table\n2 ).\nFigure 1 The clinical pregnancy rate of patients concerning TSH and anti-TPO\npositivity\nThe clinical pregnancy rate of patients concerning TSH and anti-TPO\npositivity\nFigure 2 The clinical pregnancy rate of patients about TSH and anti-TG\npositivity\nThe clinical pregnancy rate of patients about TSH and anti-TG\npositivity\n\nThe fertility treatment outcome in the presence of thyroid autoimmunity (TAI) and\nsubclinical hypothyroidism is contradictory ( Unuane\n et al ., 2017 ;  Medenica  et al ., 2015 ;  Karmon  et al ., 2015 ;  Jatzko  et al ., 2014 ;  Tuncay  et al ., 2018 ). In this study, we investigated\nthe fertility outcome in euthyroid women treated with IUI concerning the TSH\nthreshold and antithyroid antibodies. We found no significant differences in\nfertility outcomes among euthyroid women between the groups. The clinical pregnancy\nrate was similar between the two groups. 59 patients (15.2%) out of the 397 patients\nin the low-TSH group (Control Group) became pregnant, whereas the clinical pregnancy\nrate was 19/110 (17.3%) in the subclinical hypothyroidism group (Study Group).\nIn the euthyroid patient group with women of normal upper TSH values we have found\nsimilar IUI outcomes compared to women with baseline TSH <2.5 mIU/L.\nUnexpectedly, some of the previous studies also showed results similar to those from\nour study; the women with a TSH score of >2.5 mIU/L before IUI had a higher birth\nrate after a clinical pregnancy and lower spontaneous abortion risk ( Tuncay  et al ., 2018 ;  Jatzko  et al ., 2014 ).  Reh  et al . (2010)  observed\nthat there was no significant difference in clinical pregnancy or birth rates\nbetween TSH levels of 0.4-2.4 mIU/L and women above 2.5 mIU/L in the infertile\npopulation. They did not report any difference in miscarriage rates in the low and\nhigh TSH groups ( Reh  et al .,\n2010 ). In another study carried out by  Karmon  et al . (2015) , there was no significant\ndifference in clinical pregnancy rates among women with TSH levels of 0.4-2.4 mIU/L\nand levels > 2.5 mIU/L. In addition, they found that preconceptional TSH levels\nwere inversely associated with spontaneous abortion and positively associated with\nlive birth after clinical pregnancy ( Karmon\n et al ., 2015 ).\nThe American Thyroid Association supported the 2012 guidelines on hypothyroidism\nmanagement in pregnancy ( Garber  et\nal ., 2012 ). The document strengthens the idea of keeping TSH\nlevels at <2.5 mIU/L in women with hypothyroidism during the first trimester of\npregnancy. Guidelines should also recommend treatment if TSH levels for euthyroid\nwomen are 2.5 mIU/L or higher in the first trimester or in those planning a\npregnancy. This supports the view that physiologically HCG cross-reacts with the TSH\nreceptor and causes a decrease in TSH levels ( Gilbert  et al ., 2008 ).\nIn addition, many studies have redefined the TSH reference intervals in pregnancy and\nargued that there should be lower values in the first trimester ( Springer  et al ., 2009 ;  Garber  et al ., 2012 ;  Ödöl et al., 2009 ). However,\nthere is no evidence that pre-pregnancy outcome in early euthyroid women with high\nnormal TSH levels has altered early cycle and pregnancy outcomes. Furthermore, since\ngeneral screening is not recommended, it is difficult to make a decision to\nintervene in the high normal TSH values found incidentally in a non-pregnant\nasymptomatic patient ( Committee on Patient Safety and\nQuality Improvement; Committee on Professional Liability, 2007 ).\nRecent studies in pregnant women in Asia (China, Korea, and India) have shown that\nthere is only a minimal reduction in the upper reference level ( Li  et al ., 2014 ;  Moon  et al ., 2015 ). According\nto these results, in the recent guidelines of the American Thyroid Association, the\nlower reference range of TSH decreased by about 0.4 mIU/L, the upper reference range\ndecreased by about 0.5 mIU/L. This corresponds to a TSH upper limit of 4.0 mIU/L for\npatients in the first trimester ( Alexander  et\nal ., 2017 ). In our study, no cut-off limit for TSH can be\nfound to predict pregnancy. A recent guide from the  Practice Committee of the American Society for Reproductive Medicine\n(2015)  states that there is insufficient data to indicate that TSH levels\nbetween 2.5 and 4 mIU/L are associated with abortion and pregnancy side effects.\nIn a study by  Negro  et al .\n(2010) , in 4,123 thyroid antibody-negative women, it was reported that\nthe loss of pregnancy below 11 weeks was higher in people with TSH levels of 2.5-5\nmIU/L. There may be a few reasons for this. The authors did not work on the\ninfertile population, but included women who were in their first trimester with\nspontaneous pregnancies. In their study, all TSH levels were measured in the\npreconceptional period. This difference can be explained in part as follows; women\nwith TSH levels ≥2.5 mIU/L in the first trimester may have higher levels\nbefore pregnancy if TSH drops in early gestation, as suggested in the literature\n( Gilbert  et al ., 2008 ).\nIn addition, over-stimulation appears to influence TSH levels ( Gracia  et al ., 2012 ). Future studies should\nclarify the potential benefits of treatment of women with high normal TSH levels who\nare already pregnant and asymptomatic, or who plan to become pregnant (naturally or\notherwise).\nThe strengths of this study include the large sample size and its unique population\nof women undergoing IUI, which allowed the uniform assessment of preconceptional\nlevels of TSH. A related point is that all the patients in our center routinely\nundergo TSH measurement before receiving IUI treatments.\nDespite these advantages, an associated limitation is that the live birth,\nspontaneous abortion and other obstetric or fetal end points of our subjects were\nnot available. Further evaluation of this relation is necessary to rule out the\npossibility of chance and unmeasured confounding.\nTSH and TAI were independently associated with pregnancy outcomes after spontaneous\nconception or ART ( Thangaratinam  et\nal ., 2011 ). One review showed antithyroid antibodies were\nnot associated with increased reproductive loss in patients submitted to ART\ntreatments ( Leiva  et al .,\n2017 ). In two meta-analyses carried out with ART ( Busnelli  et al ., 2016 ;  Toulis  et al ., 2010 ), TAI has a potentially\nharmful effect on pregnancy. In a meta-analysis involving twelve studies,  Busnelli  et al . (2016)  showed a\nnegative TAI effect of in terms of an increased risk of miscarriage and a decreased\nchance of live birth. In another meta-analysis involving four studies,  Toulis  et al . (2010)  showed a\n2-fold increase in risk of miscarriage for TAI-positive patients, but no significant\neffect on clinical pregnancy and live birth rates. In another study, pregnancy\noutcomes of 114 TAI-positive and 495 TAI-negative infertile women were compared and\nthere was no significant difference in implantation, fertilization rate, pregnancy\nrates and live birth rates ( Łukaszuk et al.,\n2015 ).  Tan  et al .\n(2014)  concluded that pregnancy outcome was comparable between women with\nand without TAI after-ICSI, but TAI status did not affect ICSI outcomes alone.\nSeveral hypotheses have been proposed to explain the possible causal relationship\nbetween TAI and negative obstetric outcome. First, TAI can lead to a general immune\nimbalance, implantation failure targeting the reproductive tract. Thus, thyroid\nantibodies are considered to be among the causes of fertility problems and recurrent\npregnancy loss. Second, thyroid antibodies may cause thyroid function decline as an\nundesirable pregnancy outcome. A positive TAI status increases the risk of\ndeveloping (sub) clinical hypothyroidism ( Medici\n et al ., 2014 ). In Unuane's study, the baseline\ncharacteristics of both patient groups were similar. There was a significant higher\nmean TSH in the anti-TPO positive group upon the fertility treatment onset ( Unuane  et al ., 2017 ).\nIn conclusion, with this large prospective cohort study we could not find any\nsignificant difference in clinical pregnancy rates in women with and without\nanti-TPO antibodies and subclinical hypothyroidism who underwent IUI. We could not\nconfirm that a TSH level above 2.5 mIU/l has a negative effect on pregnancy rates.\nMore prospective studies are needed to confirm our results, which will shed new\nlight on the impact of thyroid function on IUI success. Future studies will also be\nuseful to clarify which TSH threshold for thyroid hormone replacement should be used\nfor infertile women.","source_license":"CC-BY-4.0","license_restricted":false}