Thyroid stimulating hormone levels rise after assisted reproductive technology

TSH levels after fresh embryo transfer are associated with reproductive outcomes in euthyroid women undergoing the first IVF/ICSI cycles

To investigate whether there is a relationship between TSH levels on the 14th day post embryo transfer (D14 TSH levels) and the reproductive outcomes in euthyroid women who are free from levothyroxine (LT4) treatment and undergo the first in vitro fertilization /intracytoplasmic sperm injection embryo transfer (IVF/ICSI-ET) cycles with the homogeneous ovarian stimulation protocols. This was a prospective study including a total of 599 euthyroid women undergoing the first IVF/ICSI ET cycles. Serum samples were collected and frozen on the 14th day post embryo transfer. TSH levels were measured after the confirmation of clinical pregnancy. The patients were divided into three groups (low-normal ≤ 2.5 mIU/L; high-normal 2.5-4.2 mIU/L; and high > 4.2 mIU/L) based on D14 TSH levels. Reproductive outcomes were compared among the three groups. Binary logistic regression analyses and generalized additive mixed models with smoothing splines were used to investigate the relationship between TSH levels and reproductive outcomes. D14 TSH levels were significantly elevated compared to basal TSH levels, and the degree of TSH elevation was significantly higher in pregnant women compared to that in non-pregnant women. The clinical pregnancy and live birth rates increased significantly in the high-normal D14 TSH groups, and doubled in the high D14 TSH groups compared to the low TSH groups. When adjusted by age, basal TSH, AMH, E2, endometrial thickness, type and causes of infertility, and transferred embryos, the dose-dependent relationships between D14 TSH and clinical pregnancy and live birth were observed. Obstetric outcomes in singleton or twins live birth among the different D14 TSH groups were similar. Elevated D14 TSH levels were associated with better clinical pregnancy and live birth rates, and were not associated with worse obstetric outcomes. The mechanisms to explain the phenomenon remained to be studied.

Effects of controlled ovarian stimulation on thyroid function during pregnancy

Controlled ovarian stimulation (COS) is a major component of assisted reproductive technologies. Clinically, it has been observed that, some women experience changes in thyrotropin levels following COS, which then bring about subclinical hypothyroidism and may adversely affect conception. Studies have also shown that the specific degree as well as the tendency of changes in thyroid function vary with differences in thyroid function before pregnancy, thyroid autoimmunity, the COS regimen, and the observation time point. However, the associated pathophysiological mechanism of the effects of COS on pregnancy has not yet been fully elucidated. This may be because increased estradiol levels, caused by COS, induce increased levels of thyroxine-binding globulin, resulting in a decrease in free thyroxine (FT4) level and an increase in TSH level. Conversely, it has also been observed that human chorionic gonadotropin (hCG) can act directly on thyroid cells, exerting opposite effects on FT4 and TSH levels. Additionally, the effects of COS on thyroid function may be more pronounced, especially in women with autoimmune thyroid disease or thyroid dysfunction before pregnancy, ultimately leading to subclinical hypothyroidism. Here, we review recent research progress regarding the effects of COS on thyroid function during pregnancy.

Relationship between maternal serum thyroid-stimulating hormone and in vitro fertilisation-conceived pregnancy outcomes

Background:

Thyroid dysfunction impairs female fertility and pregnancy outcome. Optimal preconception and gestational TSH level is still debatable in IVF-conceived pregnancies.

Aims:

To explore the relationships of IVF success and pregnancy outcomes with maternal serum levels of TSH (at both preconception and 12-week IVF-conceived pregnancy). Also, to confirm or refute the recommended TSH level ≤2.5μIU/mL.

Study Setting and Design:

Retrospective cohort.

Material and Methods:

158 IVF-conceived pregnant women and 117 age-matched controls non-pregnant (≤39years, BMI 18.5-38kg/m2) were recruited. Preconception and 12-week IVF-conceived pregnancy serum samples were analysed for reproductive hormones, fasting glucose, insulin and TSH levels. Data of pregnant women at 28 weeks for GDM screening (75-gram OGTT) and up until delivery were included.

Statistical Analysis:

Binary logistic regression used to predict association between preconception TSH levels and IVF success, and pregnancy outcomes. Association of delta change of hormones was determined with linear regression. Significance level P≤0.05 with 95% confidence interval (CI).

Results:

Overall, median (IQR) age was 32(6)years, BMI 25.4(6.9)kg/m2, HbA1c 5.2(0.52)% and TSH 1.82(1.4)μIU/mL. There was no significant association between preconception TSH level and IVF success rate. During the first trimester of IVF-conceived pregnancy, delta change in TSH level was associated with that of progesterone (P=0.03). 12-week gestation TSH level did not predict adverse pregnancy outcomes (i.e. onset of GDM, delivery type and premature delivery); but a higher TSH level predicted earlier delivery in weeks. There was a higher risk of delivery by caesarean section when TSH>2.5μIU/mL.

Conclusion:

Variation of maternal TSH within normal range (0.4-4.0μIU/mL) at preconception and 12-week gestation has no predictive effect on IVF success and pregnancy outcomes in IVF-pregnancy. Our data provide no support for a recommended preconception TSH level ≤2.5μIU/mL in IVF-conceived pregnancy, but rather promote a preconception TSH level within normal range.

Prior iodine exposure and impact on thyroid function during controlled ovarian hyperstimulation: A prospective study

AIMS

Iodine supplements are recommended for women planning pregnancy, but their impact on thyroid function during controlled ovarian hyperstimulation (COH) and into pregnancy is unknown. The aim of this study was to assess the impact of iodine supplementation on thyroid function during COH.

METHODS

One-hundred and six euthyroid women (thyroid stimulating hormone (TSH) 0.4-2.5 mIU/L) planning their first COH cycle were subdivided according to iodine supplementation (nil, <6 months, ≥6 months) and compared to levothyroxine (LT4)-treated controls. Serial TSH, free thyroxine, free triiodothyronine and thyroglobulin (Tg) levels were recorded at four time points: (i) baseline, (ii) day 7 ovarian stimulation, (iii) ovulation trigger and (iv) two weeks post oocyte retrieval. Oocyte numbers, fertilisation rates and pregnancy outcome were recorded.

RESULTS

TSH increased during COH for those women taking iodine supplements for ≥6 months (P = 0.025). One quarter recorded a TSH level >2.5 mIU/L before embryo transfer. A similar increase in TSH was demonstrated by LT4-dependent controls (P = 0.024) but not the remaining subgroups. Tg levels did not change during COH in any group but decreased significantly post oocyte retrieval if nil iodine (P < 0.0001) or supplemented for ≥6 months (P < 0.005). Iodine supplementation did not influence oocyte count, fertilisation or implantation rates. Women taking iodine for <6 months were four times more likely to achieve a live birth than women taking iodine for longer.

CONCLUSIONS

Women taking iodine supplements for ≥6 months are less able to adapt to the thyroidal demands of COH, with responses comparable to LT4-dependent patients.

Changes in thyroid function during controlled ovarian hyperstimulation (COH) and its impact on assisted reproduction technology (ART) outcomes: a systematic review and meta-analysis

BACKGROUND

To investigate the thyroid function changes during controlled ovarian hyperstimulation (COH) and ascertain its impact on reproductive outcomes.

METHODS

We conducted meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive literature search was performed to identify studies reported changes in thyroid parameters during COH. We analyzed thyroid-stimulating hormone (TSH) levels, free thyroxin (fT4) levels, changes in estrogens (E2), thyroxine-binding globulin (TBG), relative risks (RRs) of clinical pregnancy rate (CPR), live birth rate (LBR), and mean difference (MD) of TSH increment between the miscarriage group and ongoing pregnancy group.

RESULTS

This meta-analysis included fifteen individual studies (n = 1665 subjects). At the end of COH, the mean TSH (2.53 mIU/L; 95% CI, 2.19 to 2.88; I² = 92.9%) exceeded the upper limit (2.5 mIU/L) and remained above the threshold until one month following embryo transfer (ET). Thyroxin decreased from baseline to the end of COH (-0.18 ng/l; 95% CI, -0.35 to 0.00; I² = 92.2%). The CPR and LBR of patients with TSH exceeding the cutoff after COH were significantly lower than those of patients with TSH below the threshold (CPR: RR, 0.62; 95% CI, 0.47 to 0.82; I² = 0.0% and LBR: RR, 0.64; 95% CI, 0.44 to 0.92; I² = 0.0%). The MD of the increment in TSH levels between the miscarriage and ongoing pregnancy groups was 0.40 mIU/L (95% CI, 0.15 to 0.65; I² = 0.0%).

CONCLUSIONS

This meta-analysis shows that TSH increases and fT4 decreases during COH. COH-induced thyroid disorder impairs reproductive outcomes.

Thyroid function modifications in women undergoing controlled ovarian hyperstimulation for in vitro fertilization: a systematic review and meta-analysis

OBJECTIVE

To investigate the impact of controlled ovarian hyperstimulation (COH) for in vitro fertilization (IVF) on thyroid function.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Infertile women undergoing conventional IVF or intracytoplasmic sperm injection.

INTERVENTION(S)

Systematic search of PubMed, MEDLINE, Embase, Scopus, and Web of Science from inception until November 2020. Studies could be included only if they met the following criteria: subjects were classified as euthyroid or hypothyroid; serum thyroid-stimulating hormone (TSH) and/or free thyroxine (FT4) levels were evaluated before COH; and the same thyroid function test was reassessed after COH (i.e., at the time of trigger for final follicle maturation and/or at pregnancy test).

MAIN OUTCOME MEASURE(S)

Mean difference (MD) between the serum TSH or FT4 levels assessed after COH and before COH.

RESULT(S)

In euthyroid women, the serum TSH levels assessed at the time of trigger and at the time of pregnancy test were significantly higher than those at baseline (MD: 0.69 mIU/L, 95% confidence interval [CI]: 0.30-1.08, I² = 93% and MD: 0.67, 95% CI: 0.49-0.85, I² = 72%, respectively). The serum FT4 levels did not undergo significant changes. Subanalysis confirmed an increase in the TSH level after restricting the analysis to women treated with gonadotropin-releasing hormone agonist protocols and to those who achieved pregnancy. A pronounced increase in the TSH level was observed in women treated for hypothyroidism (MD: 1.50 mIU/L, 95% CI: 1.10-1.89, I² = 0%).

CONCLUSION(S)

Pooling of the results showed a significant increase in serum TSH level in women undergoing COH for IVF. This change was particularly pronounced in women treated for hypothyroidism. New thyroid function screening strategies for women undergoing COH are warranted.

2021 European Thyroid Association Guideline on Thyroid Disorders prior to and during Assisted Reproduction

Severe thyroid dysfunction may lead to menstrual disorders and subfertility. Fertility problems may persist even after restoring normal thyroid function, and then an assisted reproductive technology (ART) may be a solution. Prior to an ART treatment, ovarian stimulation is performed, leading to high oestradiol levels, which may lead to hypothyroidism in women with thyroid autoimmunity (TAI), necessitating levothyroxine (LT4) supplements before pregnancy. Moreover, women with the polycystic ovarian syndrome and idiopathic subfertility have a higher prevalence of TAI. Women with hypothyroidism treated with LT4 prior to ART should have a serum TSH level <2.5 mIU/L. Subfertile women with hyperthyroidism planning an ART procedure should be informed of the increased risk of maternal and foetal complications, and euthyroidism should be restored and maintained for several months prior to an ART treatment. Fertilisation rates and embryo quality may be impaired in women with TSH >4.0 mIU/L and improved with LT4 therapy. In meta-analyses that mainly included women with TSH levels >4.0 mIU/L, LT4 treatment increased live birth rates, but that was not the case in 2 recent interventional studies in euthyroid women with TAI. The importance of the increased use of intracytoplasmic sperm injection as a type of ART on pregnancy outcomes in women with TAI deserves more investigation. For all of the above reasons, women of subfertile couples should be screened routinely for the presence of thyroid disorders.

The impact of TSH levels on clinical outcomes 14 days after frozen-thawed embryo transfer

Background

The aim of this study was to investigate the impact of TSH levels on clinical outcomes 14 days after frozen-thawed embryo transfer.

Methods

Blood samples were collected on the first visit to our department and 14 days after embryo transfer. Women were divided into three groups based on D14 TSH levels, which were compared to basal TSH levels in groups with different clinical outcomes. TSH levels between pregnant and nonpregnant women were also compared.

Results

The clinical pregnancy rate in women with lower TSH levels 14 days after transfer was slightly but significantly lower (56%, P = 0.05) compared to those with higher TSH levels. Furthermore, TSH levels were significantly elevated 14 days after transfer compared to basal TSH levels in pregnant women and in women who successfully became pregnant (P < 0.001, respectively).

Conclusions

Elevated TSH levels 14 days after embryo transfer compared to basal TSH levels seem to play a protective role and predict favorable clinical outcomes under specific conditions.

The Impact of Preconception TSH on the Reproductive Outcomes of Infertile Women Undergoing the First Fresh D3 Embryo Transfer Cycle

PURPOSE

To investigate the association between high-normal preconception TSH levels and reproductive outcomes in infertile women undergoing the first fresh D3 embryo transfer.

METHODS

This was a retrospective study. Euthyroid patients undergoing the first fresh D3 embryo transfer from January 2018 to May 2019 were initially included. The patients were divided into a low-TSH (0.27-2.5 mIU/L) group and a high-normal TSH (2.5-4.2 Miu) group. The reproductive outcomes were compared between the groups.

RESULTS

A total of 1786 women were ultimately included, in which 1008 of whom had serum TSH levels between 0.27 and 2.5 mIU/L and 778 of whom had serum TSH levels between 2.5 and 4.2 mIU/L. The patients were highly homogeneous in terms of general characteristics. High-normal TSH levels had no adverse impact on the clinical pregnancy rate, miscarriage rate, or live birth rate (respectively, aOR = 0.92, 1.30, and 0.88 and P = 0.416, 0.163, and 0.219). No significant differences were observed in terms of gestational age, single live birth rates, and birth weight, or birth length.

CONCLUSION

High-normal TSH levels did not significantly influence reproductive outcomes in infertile women undergoing the first fresh D3 embryo transfer. Further studies are needed to test whether the results might be applicable to a wider population.

High-Normal Preconception TSH Levels Have No Adverse Effects on Reproductive Outcomes in Infertile Women Undergoing the First Single Fresh D5 Blastocyst Transfer

PURPOSE

To investigate the association between high-normal preconception TSH levels and reproductive outcomes in infertile women undergoing the first single fresh D5 blastocyst transfer.

METHODS

This was a retrospective study. Euthyroid patients undergoing the first single fresh D5 blastocyst transfer from January 2018 to May 2019 were initially included. The patients were divided into a low TSH (0.27-2.5 mIU/L) group and a high-normal TSH (2.5-4.2 mIU/L) group. The reproductive outcomes were compared between the groups.

RESULTS

A total of 824 women were ultimately included, 460 of whom had serum TSH levels less than 2.5 mIU/L and 364 of whom had serum TSH levels between 2.5 and 4.2 mIU/L. The patients were highly homogeneous in terms of general characteristics. High-normal TSH levels had no adverse impact on the clinical pregnancy rate, miscarriage rate, or live birth rate (respectively, aOR = 0.84, 0.65, 0.61, and P=0.234, 0.145, 0.083). No significant differences were observed in terms of gestational age, single live birth rates, birth weight, or birth length.

CONCLUSION

High-normal TSH levels did not significantly influence reproductive outcomes in infertile women undergoing the first single fresh D5 blastocyst transfer. Further studies are needed to test whether the results might be applicable to a wider population.

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.

Levothyroxine supplementation on assisted reproduction technology (ART) outcomes in women with subtle hypothyroidism: a retrospective study

The need for treating subclinical hypothyroidism (SCH) in women undergoing assisted reproduction technology (ART) is under debate. Moreover, it is known that controlled ovarian hyperstimulation (COH) protocols may impair the thyroidal axis. Therefore, we evaluated if levothyroxine (L-T4) supplementation in SCH women before undergoing ART positively affects the main reproductive outcomes. We retrospectively analyzed in vitro fertilization (IVF) data of 4147 women submitted to 6545 cycles in a tertiary care IVF Center (January 2009-December 2014). L-T4 (1.4-2.0 mcg/kg) treatment was offered to all women with a pre-cycle TSH >2.5 mIU/L before starting COH and main ART outcomes were compared in euthyroid and L-T4-treated women undergoing ART. Among 4147 women, 1074 (26%) were affected by SCH and were treated with L-T4 before COH was started. No statistically significant differences among L-T4-treated and euthyroid women group were observed regarding pregnancy rate, respectively, per cycle (27.67% vs 26.37%; p = .314) and per embryo transfer (30.13% vs 29.17%; p = .489), live birth rate, respectively, per cycle (21.58% vs 20.38%; p = .304) and per embryo transfer (23.49 vs 22.54%; p = .449) and the rest of primary and secondary efficacy endpoints. Early L-T4 treatment for infertile women with a subtle thyroid dysfunction may mitigate and protect from the negative effects of SCH in the setting of ART, and may preventively overcome also the negative impact of COH on thyroidal axis.

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.

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.

Outcome of in vitro fertilization in women with subclinical hypothyroidism

BACKGROUND

Previous studies examining associations between subclinical hypothyroidism (SCH) with in vitro fertilization (IVF) outcome indicate some benefits of levothyroxine (LT4) treatment. But IVF outcomes in treated SCH women whose serum Thyroid Stimulating Hormone (TSH) concentration did and did not exceed 2.5 mIU/L before the IVF cycle has not been studied thoroughly.

METHODS

In this study, we performed a prospective cohort study with 270 treated subclinical hypothyroidism patients undergoing their first IVF retrieval cycle at a single cite.

RESULTS

SCH in women receiving LT4 replacement with a basal TSH level between 0.2-2.5mIU/L displayed a similar rate of clinical pregnancy (47.4% vs 38.7%, P = .436), miscarriage (7.4% vs 16.7%, P = .379) and live birth (43.9% vs 32.3%, P = .288) compared to women with a basal TSH level between 2.5-4.2 mIU/L.

CONCLUSION

Strictly controlled TSH (less than 2.5 mIU/L) before IVF may have no effect on the pregnancy rate in LT4 treated SCH women.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Thyroid function and autoimmunity during ovarian stimulation for intracytoplasmic sperm injection

The aim of the present study was to assess changes in thyroid function and thyroid autoimmunity (TAI) throughout ovarian stimulation (OS) for intracytoplasmic sperm injection (ICSI) and the association of these changes with ICSI outcome. A flexible gonadotrophin-releasing hormone (GnRH) antagonist protocol was used in 42 women and their thyroid function and TAI were assessed at baseline and five times during OS (Days 3 and 5 of the menstrual cycle, the day of hCG administration, the day of ovum pick-up and the day of the pregnancy test). The primary outcome measure was the change in thyroid function throughout OS. No overall change was recorded in thyrotropin-stimulating hormone (TSH) concentrations throughout OS (P = 0.066). In women who became pregnant (n = 8), an increase in TSH concentrations was noted on the day of the pregnancy test compared with Day 3 of the menstrual cycle (3.410 ± 1.200 vs 2.014 ± 0.950 μIU mL–1, respectively; P = 0.001; mean ± s.d.). TAI was present in 11 of 42 women. Biochemical pregnancy was negatively correlated with changes in TSH (r = –0.7, P = 0.004). No such association was noted regarding the live birth rate. The present study provides evidence that TSH concentrations could increase during OS, especially in women who become pregnant.

THYROID DYSFUNCTION AND INFERTILITY TREATMENT

Objective

To find out the relationship of thyroid hormone profile of females with outcomes after intra cytoplasmic sperm injection (ICSI).

Method

It was a cross sectional study conducted in Islamabad Clinic Serving Infertile Couple from June 2013 till August 2015. T3 (triiodo thyronine), T4 (thyroxine) and TSH (thyroid stimulating hormone) of 168 consented females was estimated after they underwent the first step of treatment protocol (ovarian down regulation) for ICSI. Pregnant group had ß hCG result more than 25 IU/mL while the rest were included in the non-pregnant group. Both groups were compared by using independent sample t-test. Pearson correlation coefficient was used to associate T3 and T4 with other pregnancy variables with their significance.

Results

Non pregnant women had significantly higher mean values for T3 and T4 as compared to pregnant women (p <0.05, p<0.01). Difference in mean TSH value between non-pregnant and pregnant women was not significant p=0.08. It was found that T4 gave significant negative association with grading of embryo-I, blastocysts formed, thickness of endometrium and number of gestational sacs.

Conclusion

Disturbance in thyroid profile with raised T4 levels leads to alteration in endometrial thickness and quality of embryos required for implantation and hence conception.

THE LONG-TERM IMPACT OF CONTROLLED OVARIAN HYPERSTIMULATION ON THYROID FUNCTION

OBJECTIVE

Evidence on the long-term impact of controlled ovarian hyperstimulation (COH) on thyroid function is scarce. To investigate this, we report on serum thyroid-stimulating hormone (TSH) modifications in euthyroid and hypothyroid women during COH and 3 months after the end of the stimulation cycle.

METHODS

Women who underwent in vitro fertilization (IVF) and who did not become pregnant were eligible. Cases were women with treated hypothyroidism and basal serum TSH <2.5 mIU/L. Controls were euthyroid women matched to cases by age and basal serum TSH. Women could be included if serum TSH was available at 4 time points: prior to initiating COH (time 1); at the time of human chorionic gonadotropin (hCG) administration (time 2); 16 days after hCG administration (time 3); and 3 months after the end of the IVF cycle (time 4).

RESULTS

Thirty-seven case-control pairs were included. Serum TSH at times 1, 2, 3, and 4 was 1.7 ± 0.6, 3.1 ± 1.4, 3.1 ± 1.3, and 2.7 ± 1.7 mIU/L, and 1.7 ± 0.6, 2.9 ± 1.0, 2.7 ± 1.0, and 1.9 ± 0.7 mIU/L among cases and controls, respectively. A statistically significant difference emerged at time 4 (P<.001). In both groups, serum TSH was higher at time 4 compared to time 1. Serum TSH exceeded the recommended threshold of 2.5 mIU/L at time 4 in 51% of cases (95% confidence interval [CI], 35 to 68%) and in 16% of controls (95% CI, 4 to 28%) (P = .003).

CONCLUSION

COH seems to have a long-term impact on TSH levels. The magnitude of this effect is particularly pronounced in hypothyroid women.

Levothyroxine dose adjustment in hypothyroid women achieving pregnancy through IVF

OBJECTIVE

About one out of two women with primary hypothyroidism has to increase the dosage of exogenous levothyroxine (L-T4) during pregnancy. Considering the detrimental impact of IVF on thyroid function, it has been claimed but not demonstrated that L-T4 dose adjustment may be more significant in hypothyroid women who become pregnant after IVF.

DESIGN

Retrospective cohort study.

METHODS

Hypothyroid-treated women who achieved a live birth through IVF were reviewed. Women could be included if thyroid function was well compensated with L-T4 before the IVF cycle (i.e., serum TSH <2.5  mIU/l and serum free T4 within the normal range). Serum TSH and dose adjustment were evaluated at five time points during pregnancy. The trimester ranges for serum TSH considered as reference to adjust L-T4 therapy were 0.1-2.5  mIU/l for the first trimester, 0.2-3.0  mIU/l for the second trimester, and 0.3-3.0  mIU/l for the third trimester.

RESULTS

Thirty-eight women were selected. During the whole pregnancy 32 women (84%; 95% CI: 72-96%) required an increase in the dose of L-T4. In most cases (n=28), this occured within the first 5-7 weeks of gestation (74%, 95% CI: 58-85%). At 5-7 weeks of gestation, the median (interquartile range) increase of L-T4 dose for the whole cohort was 26% (0-50%). At 30-32 weeks, it was 33% (14-68%). In order to identify predictive factors of dose adjustment, we compared women who did (n=28) and did not (n=10) adjust L-T4 dosage at 5-7 weeks' gestation. Significant differences emerged for thyroid autoimmunity prevalence and for the distribution of hypothyroidism aetiology.

CONCLUSIONS

The vast majority of hypothyroid-treated women who achieve pregnancy through IVF need an increase in the L-T4 dose during gestation. This requirement tends to occur very early during gestation.

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.

Thyroid axis dysregulation during in vitro fertilization in hypothyroid-treated patients

BACKGROUND

While there is a large body of evidence showing a significant impact of controlled ovarian hyperstimulation (COH) on thyroid function in euthyroid patients undergoing in vitro fertilization (IVF), information on the effect of this treatment on thyroid axis equilibrium in hypothyroid-treated patients is insufficient. The goal of this prospective study was to investigate serum thyroid-stimulating hormone (TSH) modifications in hypothyroid-treated patients during IVF.

METHODS

Hypothyroid-treated women selected for IVF between November 2010 and December 2011 were considered for study entry. They were eligible if serum TSH tested the month preceding the IVF cycle was 0.4-2.5 mIU/L. Additional inclusion criteria were as follows: (1) a certified diagnosis of clinical or subclinical hypothyroidism; (2) consumption of at least 25 μg of levothyroxine daily; (3) serum free triiodothyronine and free thyroxine tested the month preceding the IVF cycle within the reference range; (4) no previous IVF cycles; (5) regular menstrual cycles; and (6) day 3 serum follicle-stimulating hormone <12 IU/mL and anti-Müllerian hormone >0.5 ng/mL. Serum TSH was tested at three time points: between day 1 and day 8 of the cycle during the month preceding the start of controlled ovarian hyperstimulation (COH), at the time of human chorionic gonadotropin (hCG) administration and at 16 days after hCG administration.

RESULTS

Seventy-two women met our selection criteria. The serum levels of TSH at basal assessment, at the time of hCG administration, and at 16 days after hCG administration were 1.7 ± 0.7, 2.9 ± 1.3, and 3.2 ± 1.7 mIU/L, respectively. All pairwise comparisons were statistically significant. Serum TSH exceeded the threshold of 2.5 mIU/L in 46 subjects at the time of hCG administration (64%, [CI: 53-75%]) and in 49 subjects 16 days after hCG administration (68%, [CI: 57-79%]).

CONCLUSIONS

Serum TSH increased considerably during COH in adequately treated hypothyroid women undergoing IVF. We suggest strictly monitoring these women during IVF cycles and, if necessary, promptly adjusting the levothyroxine dose. This is the most pragmatic approach but, to date, it is not supported by clinical evidence. Further studies aimed at clarifying the most suitable therapeutic strategy are thus warranted.