Association of Overt and Subclinical Hyperthyroidism During Weeks 4–8 with Adverse Pregnancy Outcomes

The Thyroid Hormone Axis and Female Reproduction

Thyroid function affects multiple sites of the female hypothalamic-pituitary gonadal (HPG) axis. Disruption of thyroid function has been linked to reproductive dysfunction in women and is associated with menstrual irregularity, infertility, poor pregnancy outcomes, and gynecological conditions such as premature ovarian insufficiency and polycystic ovarian syndrome. Thus, the complex molecular interplay between hormones involved in thyroid and reproductive functions is further compounded by the association of certain common autoimmune states with disorders of the thyroid and the HPG axes. Furthermore, in prepartum and intrapartum states, even relatively minor disruptions have been shown to adversely impact maternal and fetal outcomes, with some differences of opinion in the management of these conditions. In this review, we provide readers with a foundational understanding of the physiology and pathophysiology of thyroid hormone interactions with the female HPG axis. We also share clinical insights into the management of thyroid dysfunction in reproductive-aged women.

Maternal hyperthyroidism alters the immunological mediators profile and population of natural killers cells in decidua of rats

Decidual immunological mediators modulate placental formation, decidualization and fetal development. However, the effect of maternal hyperthyroidism on decidual immunology needs further research. The aim of this study was to evaluate the population of uterine natural killer cells (uNKs) and the expression of immunological mediators in the decidua of female rats throughout pregnancy. Wistar rats were used and hyperthyroidism was induced by daily administration of L-thyroxine (T4) throughout pregnancy. The population of uNK cells in decidua was evaluated by immunostaining Lectin DBA, as well as the expression of interferon γ (INFγ), macrophage migration inhibitory factor (MIF), interleukin 15 (IL-15) and inducible nitric oxide synthase (iNOS) at 7, 10, 12, 14 and 19 days of gestation (DG). Maternal hyperthyroidism reduced the DBA+ uNK cell population in the decidua at 7 (P < 0.05) and 10 (P < 0.01) DGs compared to that in the control group, while it increased in the basal decidua (P < 0.05) and metrial gland (P < 0.0001) at the 12th DG. Hyperthyroidism also increased immunostaining of IL-15 (P < 0.0001), INFγ (P < 0.05), and MIF (P < 0.05) in the 7th DG, and increased immunostaining of IL-15 (P < 0.0001) and MIF (P < 0.01) in ^the 10th DG. However, excess thyroxine reduced IL-15 expression in the metrial gland and/or basal decidua in the 12th (P < 0.05), 14th (P < 0.01), and 19th (P < 0.001) DGs, as was also observed for INFγ in the basal decidua (P<0.001) and metrial gland (P < 0.0001) in the 12th DG. Regarding iNOS, an antiinflammatory cytokine, lower expression was observed in the basal decidua of hyperthyroid animals at 7 and 12 DGs (P < 0.05), whereas an increase occurred in the 10th DG (P < 0.05). These data demonstrate that maternal hyperthyroidism in female rats, particularly between 7 and 10 DGs, reduces the population of DBA+ uNKs in the decidua and increases the expression of inflammatory cytokines, suggesting a more proinflammatory environment in early pregnancy caused by this gestational disease.

Maternal subclinical hyperthyroidism and adverse pregnancy outcomes considering the iodine status: Tehran thyroid and pregnancy study

BACKGROUND

Unlike overt thyroid diseases, the impacts of subclinical thyroid dysfunction, especially subclinical hyperthyroidism (SH), on adverse pregnancy outcomes are inconclusive.

OBJECTIVE

We aimed to investigate the effect of maternal SH on adverse maternal and neonatal outcomes based on urinary iodine concentration (UIC).

METHODS

A secondary analysis was run on data collected in the Tehran Thyroid and Pregnancy study (TTPs). We used the data of 131 women with SH and 1650 cases of euthyroid. Serum levels of thyroid-stimulating hormone (TSH), thyroxine (T4), free thyroxine index (FT4I), and thyroid peroxidase antibody (TPOAb) were assessed at the first prenatal visit. A generalized linear regression model was applied to identify the effect of SH on the pregnancy outcomes based on UIC, and the effects were estimated with a 95% confidence interval.

RESULTS

Preterm delivery was observed in 12.3% of women with SH and 6.7% of those with euthyroid (P = 0.03). Women with TSH< 0.3 mIU/L had a higher odds of preterm delivery than those with TSH≥ 0.3 regardless of urine iodine cut-off [OR= 2.27; 95% CI: (1.15, 4.48), p = 0.02]. Among those with UIC levels≥ 150 μg/L, the odds ratio of preterm delivery was 4.61 folds higher in the SH group compared to those with euthyroid [95%CI: (1.36, 15.71), p = 0.01)]. No significant difference between these two study groups was found in Neonatal Intensive Care Unit admission. Moreover, the results revealed no statistically significant difference in the means of neonatal anthropometric parameters in the SH and euthyroid groups in none of the subgroups of UIC (<150 or ≥150 µg/l).

CONCLUSIONS

According to our results, maternal SH appears to be a risk factor for preterm delivery. This effect is more pronounced in women with higher UIC than those with lower UIC.

Associations of bisphenol exposure with thyroid hormones in pregnant women: a prospective birth cohort study in China

Bisphenols are endocrine disruptor chemicals that disrupt thyroid hormone homeostasis. However, evidence on the effects of bisphenol mixtures on thyroid hormones are insufficient. Therefore, the present study aimed to explore the effects of bisphenol substitutes and bisphenol mixtures on thyroid hormones during pregnancy. The study was conducted among 446 pregnant women in the Guangxi Zhuang Birth Cohort (GZBC), China. In multiple linear regressions, compared with the low-exposure group, bisphenol S (BPS) concentrations in the middle-exposure group led to a 10.90% (95% CI: - 18.16%, - 2.99%) decrease in triiodothyronine (T3) levels in the first trimester; tetrabromobisphenol A (TBBPA) levels in the middle-exposure group led to an 8.26% (95% CI: - 15.82%, - 0.01%) decrease in T3 levels in the first trimester; bisphenol B (BPB) levels in the middle-exposure group led to higher free thyroxine (FT4) levels (9.84%; 95% CI: 1.73%, 18.60%) in the second trimester; bisphenol F (BPF) in the middle-exposure group led to higher FT4 levels (8.59%, 95% CI: 0.53%, 17.31%) in the second trimester; and TBBPA levels in the high-exposure group led to a 9.39% (95% CI: 1.46%, 17.93%) increase in FT4 levels in the second trimester. The Bayesian kernel machine regression (BKMR) and restricted cubic spline (RCS) models showed a U-shaped dose-response relationship between bisphenol A (BPA) and free triiodothyronine (FT3) (p < 0.01) as well as BPS and FT4 (p < 0.05). Nonlinear relationships were also observed between the bisphenol mixture and FT3. Overall, maternal bisphenol exposure affected thyroid hormone levels during pregnancy. This study provides evidence that BPB, BPF, BPS, and TBBPA are unsafe substitutes for BPA, as well as the overall effect of bisphenols on adverse health in human beings.

Thyroid hormones: Metabolism and transportation in the fetoplacental unit

The thyroid hormones (THs), thyroxine (T4) and triiodothyronine (T3), are of vital importance for fetal development. The concentration of THs in fetal circulation varies throughout gestation and differs from the concentration in the maternal serum, indicating the presence of maternal-fetal thyroid homeostasis regulatory mechanisms in the placenta. The passage of THs from maternal circulation to fetal circulation is modulated by plasma membrane transporters, enzymes, and carrier proteins. Monocarboxylate transporter 8, iodothyronine deiodinases (DIO2 and DIO3), and transthyretin are especially involved in this maternal-fetal thyroid modulation, shown by a greater expression in the placenta. THs also play a role in placental development and as expected, abnormal variations in TH levels are associated with pregnancy complications and can result in damage to the fetus. Although new evidence regarding TH regulation during pregnancy and its effects in the mother, placenta, and fetus has been published, many aspects of these interactions are still poorly understood. The objective of this review is to provide an evidence-based update, drawn from current data, on the metabolism and transport of THs in the placenta and their vital role in the maternal-fetal relationship.

Preconception thyroid-stimulating hormone levels and adverse pregnancy outcomes

OBJECTIVE

Evidence for the association between subclinical thyroid dysfunction before conception and its pregnancy outcomes is inconsistent. Thus, we evaluated the relationship between preconception thyroid-stimulating hormone (TSH) levels and adverse pregnancy outcomes.

DESIGN

Retrospective cohort study.

METHODS

A total of 50,217 women without prior thyroid disease who became pregnant within 1 year after undertaking a routine TSH test in the Chongqing Municipality of China (2010-2016) were studied. Restricted cubic spline regression and logistic regression were used to estimate the association between preconception TSH levels and pregnancy outcomes. The main outcomes were individual and composite adverse pregnancy outcomes (CAPOs) comprising pregnancy loss, small for gestational age, large for gestational age, and preterm birth.

RESULTS

Incidence of CAPO was 24.19%. Increased preconception TSH level was positively associated with CAPO (odds ratio [OR]/SD: 1.04, 95% confidence interval [CI]: 1.01-1.07) when TSH was ≥2.1 mIU/L, positively associated with pregnancy loss (OR/SD: 1.06, 95% CI: 1.01-1.12) when TSH was <2.1 mIU/L, negatively and positively associated with preterm delivery when TSH levels were <1.3 mIU/L (OR/SD: 0.90, 95% CI: 0.83-0.97) and >3.0 mIU/L (OR/SD: 1.08, 95% CI: 1.00-1.17), respectively. Women with subclinical hypothyroidism before conception were at a higher risk for CAPO (adjusted odds ratio [aOR]: 1.12, 95% CI: 1.04-1.22), while those with subclinical hyperthyroidism had a higher risk of preterm delivery (aOR: 1.31, 95% CI: 1.01-1.70).

CONCLUSIONS

Nonlinear associations were indicated between preconception TSH levels and pregnancy outcomes. Subclinical thyroid dysfunction before conception was associated with an increased risk of adverse pregnancy outcomes.

Evaluation of anti-Müllerian hormone in pre-menopausal women stratified according to thyroid function, autoimmunity and age

Background

AMH is a reliable index of ovarian reserve. It is not clear whether, or how much, thyroid function and/or thyroid autoimmunity can impair ovarian function and AMH secretion in the long term.

Aim

This retrospective cross-sectional study compared AMH levels in pre-menopausal women with/without positive thyroid autoimmunity or hypofunction.

Methods

From January 2019 to May 2022, AMH was evaluated in 250 pre-menopausal women not undergoing assisted fertility procedures who were referred to a secondary endocrine centre. Thyroid function and autoimmunity, sonographically measured thyroid volume, FSH and E2 in the early follicular phase, and PRL and progesterone in the luteal phase were also evaluated. Exclusion criteria were: age < 18 years, genetic hypogonadism, pregnancy and previous treatments that have potentially damaging effects on gonads.

Results

We evaluated 171 women (mean age ± SD: 31.5 ± 9.0 years) off L-T4 treatment and 79 women on L-T4 treatment (39.7 ± 9.5 years; P < 0.001). AMH (median, IQR, CI) was 16.1 pmol/l (7.1 – 35.7 pmol/l, 21.4 – 29.9 pmol/l) and 7.6 pmol/l (1.4 – 17.8 pmol/l, 8.6 – 14.7 pmol/l; P < 0.001), respectively. When the women were stratified according to age (18-25, 26-30, 31-35, 36-40, 41-45, > 46 years) no significant difference emerged between those on/off L-T4 treatment in groups of the same age-range. In women on- or off-L-T4 treatment, AMH was negatively related with age on univariate and multivariate analyses (P < 0.0001). In both groups, AMH was negatively related to FSH (P < 0.0001). On multivariate analysis, AMH was positively related to the age of the mother on spontaneous menopause (P = 0.006) and negatively to thyroid volume (P = 0.02) in women on L-T4. AMH levels were significantly (P = 0.03) higher in TPOAb-negative than in TPOAb-positive women, but age was significantly (P = 0.001) lower in TPOAb-negative than in TPOAb-positive women.

Conclusions

In our cohort of women, age proved to be a better predictor of AMH levels than any of the other factors linked to thyroid function and autoimmunity. Our data do not support the hypothesis that subclinical hypothyroidism and/or autoimmunity are associated with decreased ovarian reserve. However, a larger number of cases is needed in order to obtain conclusive data.

Maternal Subclinical Hyperthyroidism and Adverse Pregnancy Outcomes: A Systematic Review and Meta-analysis of Observational Studies

CONTEXT

Findings from studies evaluating adverse pregnancy outcomes in pregnant women with subclinical hyperthyroidism are conflicting and inconclusive.

OBJECTIVES

In this systematic review and meta-analysis, our aim was to evaluate the pooled odds ratio (OR) of adverse pregnancy outcomes in women with subclinical hyperthyroidism, compared to euthyroid women.

DATA SOURCES

Scopus, PubMed (including Medline), and Web of Science databases were systemically searched for regaining published studies to January 2022 examining adverse pregnancy outcomes in women with subclinical hyperthyroidism.

STUDY SELECTION

Outcomes of interest were classified into seven composite outcomes, including hypertensive disorders, preterm delivery, macrosomia/large for gestational age (LGA), pregnancy loss, adverse maternal outcomes, adverse neonatal outcomes, and adverse fetal outcomes.

DATA EXTRACTION

In this meta-analysis, both fixed and random effect models were used. Publication bias was also evaluated by Egger test and the funnel plot, and the trim and fill method was conducted in case of a significant result, to adjust the bias.

RESULTS

Of 202 records retrieved through searching databases, 11 studies were selected for the final analyses. There were no significant differences in pooled ORs of hypertensive disorders, preterm delivery, macrosomia/LGA, and pregnancy loss in pregnant women with subclinical hyperthyroidism, compared to the euthyroid controls. The pooled OR of adverse maternal, neonatal, and fetal outcomes in pregnant women with subclinical hyperthyroidism was not statistically significantly different from that of the euthyroid control group.

CONCLUSIONS

The current meta-analysis demonstrated that subclinical hyperthyroidism in pregnancy is not related with adverse maternal and fetal outcomes. Therefore, clinicians should be avoided unnecessary treatments for pregnant women with subclinical hyperthyroidism.

Epidemiology, Risk Factors, and Perinatal Outcomes of Placental Abruption-Detailed Annual Data and Clinical Perspectives from Polish Tertiary Center

Placental abruption (PA) is a separation of the placenta from the uterine wall occurring with the fetus still present in the uterine cavity. It contributes to numerous neonatal and maternal complications, increasing morbidity and mortality. We conducted a retrospective study at a tertiary perinatal care center, which included 2210 cases of labor that took place in 2015 with a PA occurrence of 0.7%. No maternal or fetal death during delivery was reported in this period. The identified PA risk factors were uterine malformations, pPROM, placenta previa spectrum, and oligohydramnios. The significant maternal PA complications identified were maternal anemia, uterine rupture, and HELLP syndrome. Preterm delivery occurred significantly more often in the PA group, and the number of weeks of pregnancy and the birth weight at delivery were both significantly lower in the PA group. PA is a relatively rare perinatal complication with very serious consequences, and it still lacks effective prophylaxis and treatment. Despite its rare occurrence, each center should develop a certain strategy for dealing with this pathology or predicting which patients are at risk. Much work is still needed to ensure the proper care of the mother and the baby in this life-threatening condition.

Association between maternal thyroid function and risk of gestational hypertension and pre-eclampsia: a systematic review and individual-participant data meta-analysis

BACKGROUND

Adequate maternal thyroid function is important for an uncomplicated pregnancy. Although multiple observational studies have evaluated the association between thyroid dysfunction and hypertensive disorders of pregnancy, the methods and definitions of abnormalities in thyroid function tests were heterogeneous, and the results were conflicting. We aimed to examine the association between abnormalities in thyroid function tests and risk of gestational hypertension and pre-eclampsia.

METHODS

In this systematic review and meta-analysis of individual-participant data, we searched MEDLINE (Ovid), Embase, Scopus, and the Cochrane Database of Systematic Reviews from date of inception to Dec 27, 2019, for prospective cohort studies with data on maternal concentrations of thyroid-stimulating hormone (TSH), free thyroxine (FT₄), thyroid peroxidase (TPO) antibodies, individually or in combination, as well as on gestational hypertension, pre-eclampsia, or both. We issued open invitations to study authors to participate in the Consortium on Thyroid and Pregnancy and to share the individual-participant data. We excluded participants who had pre-existing thyroid disease or multifetal pregnancy, or were taking medications that affect thyroid function. The primary outcomes were documented gestational hypertension and pre-eclampsia. Individual-participant data were analysed using logistic mixed-effects regression models adjusting for maternal age, BMI, smoking, parity, ethnicity, and gestational age at blood sampling. The study protocol was registered with PROSPERO, CRD42019128585.

FINDINGS

We identified 1539 published studies, of which 33 cohorts met the inclusion criteria and 19 cohorts were included after the authors agreed to participate. Our study population comprised 46 528 pregnant women, of whom 39 826 (85·6%) women had sufficient data (TSH and FT₄ concentrations and TPO antibody status) to be classified according to their thyroid function status. Of these women, 1275 (3·2%) had subclinical hypothyroidism, 933 (2·3%) had isolated hypothyroxinaemia, 619 (1·6%) had subclinical hyperthyroidism, and 337 (0·8%) had overt hyperthyroidism. Compared with euthyroidism, subclinical hypothyroidism was associated with a higher risk of pre-eclampsia (2·1% vs 3·6%; OR 1·53 [95% CI 1·09-2·15]). Subclinical hyperthyroidism, isolated hypothyroxinaemia, or TPO antibody positivity were not associated with gestational hypertension or pre-eclampsia. In continuous analyses, both a higher and a lower TSH concentration were associated with a higher risk of pre-eclampsia (p=0·0001). FT₄ concentrations were not associated with the outcomes measured.

INTERPRETATION

Compared with euthyroidism, subclinical hypothyroidism during pregnancy was associated with a higher risk of pre-eclampsia. There was a U-shaped association of TSH with pre-eclampsia. These results quantify the risks of gestational hypertension or pre-eclampsia in women with thyroid function test abnormalities, adding to the total body of evidence on the risk of adverse maternal and fetal outcomes of thyroid dysfunction during pregnancy. These findings have potential implications for defining the optimal treatment target in women treated with levothyroxine during pregnancy, which needs to be assessed in future interventional studies.

FUNDING

Arkansas Biosciences Institute and Netherlands Organization for Scientific Research.

Effect of Hyperthyroidism Control During Pregnancy on Maternal and Fetal Outcome: A Systematic Review and Meta-Analysis

CONTEXT

Although the overt hyperthyroidism treatment during pregnancy is mandatory, unfortunately, few studies have evaluated the impact of treatment on reducing maternal and fetal outcomes.

OBJECTIVE

This study aimed to demonstrate whether treatment to control hyperthyroidism manifested during pregnancy can potentially reduce maternal-fetal effects compared with euthyroid pregnancies through a systematic review with meta-analysis.

DATA SOURCE

MEDLINE (PubMed), Embase, Cochrane Library Central, LILACS/BIREME until May 2021.

STUDY SELECTION

Studies that compared, during the gestational period, treated women with hyperthyroidism versus euthyroid women. The following outcomes of this comparison were: pre-eclampsia, abruptio placentae, fetal growth retardation, gestational diabetes, postpartum hemorrhage, low birth weight, stillbirth, spontaneous abortions, premature birth.

DATA EXTRACTION

Two independent reviewers extracted data and performed quality assessments. Dichotomous data were analyzed by calculating risk differences (DR) with fixed and random effect models according to the level of heterogeneity.

DATA SYNTHESIS

Seven cohort studies were included. The results of the meta-analysis indicated that there was a lower incidence of preeclampsia (p=0.01), low birth weight (p=0.03), spontaneous abortion (p<0.00001) and preterm birth (p=0.001) favouring the euthyroid pregnant group when compared to those who treated hyperthyroidism during pregnancy. However, no statistically significant differences were observed in the outcomes: abruptio placentae, fetal growth retardation, gestational diabetes mellitus, postpartum hemorrhage, and stillbirth.

CONCLUSIONS

Our findings demonstrated that treating overt hyperthyroidism in pregnancy is mandatory and appears to reduce some potential maternal-fetal complications, despite there still being a residual risk of negative outcomes.

Obstetric outcomes in thyroid cancer survivors: A retrospective cohort study

OBJECTIVE

To investigate whether thyroid cancer survivors would have increased risks of adverse obstetric outcomes.

METHODS

Data from 154 women with a history of thyroid cancer who had a live birth at Peking University Third Hospital from January 2012 to December 2019 were collected. The control group consisted of 308 women without any thyroid disease or malignant tumor. Age and year of delivery were matched between the two groups.

RESULTS

Serum levels of thyroid stimulating hormone and free thyroxine were significantly lower and higher in thyroid cancer patients, respectively (P < 0.001). After adjusting for age, pre-pregnancy body mass index, pre-pregnancy hypertension, pre-pregnancy diabetes mellitus, previous cesarean section, and conception by in vitro fertilization/intracytoplasmic injection, adverse obstetric outcomes including preterm birth (odds ratio [OR] 0.73, 95% confidence interval [CI] 0.32-1.67), low birth weight infant (OR 1.05, 95% CI 0.44-2.50), gestational diabetes mellitus (OR 0.86, 95% CI 0.54-1.39), and pre-eclampsia (OR 1.11, 95% CI 0.34-3.57) showed no differences between thyroid cancer survivors and the control group. However, pregnant women with a history of thyroid cancer had a higher risk of abnormally invasive placentation (OR 10.57, 95% CI 1.22-91.97, P = 0.032).

CONCLUSION

Although the thyroid function status of thyroid cancer patients was different from that of pregnant women without any thyroid disease or malignancy, they would not be at a higher risk of most adverse obstetric outcomes except for abnormally invasive placentation.

The role of thyroid-stimulating hormone and thyroglobulin antibody in abnormally invasive placenta

PURPOSE

Thyroid hormones and antibodies are known to participate in angiogenesis and invasion and also thyroid hormone receptors are expressed in the placenta. We aimed to evaluate the relationship of serum levels of thyroid-stimulating hormone (TSH), thyroid hormones (TH), and anti-thyroid antibodies with abnormally invasive placenta (AIP). We also aimed to investigate whether they are related with cesarean hysterectomy and massive blood transfusion need in AIP cases.

METHODS

A total of 88 pregnant patients were enrolled in this prospective case-control study (30 with AIP, 28 with non-adherent placenta previa totalis (PPT) and 30 controls). Serum TSH, thyroid hormone [T3 (triiodothyronine) and T4 (thyroxine)] and thyroid antibodies against thyroglobulin (TgAb) and thyroid peroxidase (TPOAb) levels were studied in maternal serum at initial admission to our Perinatology Unit (at early third trimester). The factors associated with increased risk of AIP, cesarean hysterectomy, massive blood transfusion, and adverse perinatal outcomes were evaluated with multiple logistic regression analysis. Adjusted odds ratios and 95% confidence intervals were also calculated.

RESULTS

Serum TSH and TgAb levels were significantly lower in the AIP group than both PPT and control groups (p = .01, p < .001 and p < .001, p < .001 respectively). Decreased serum levels of TSH (<2.16 mIU/L) and TgAb (<2.70 mIU/L) levels and high previous cesarean section rates were found to be independently associated with AIP in pregnant women with PPT (OR: 0.4, 95% CI: 0.1-0.9; p = .04, OR: 0.7, 95%CI: 0.4-1.3, p = .02 and OR: 0.1, 95% CI: 0.1-0.5, p = .01). Decreased serum TSH and TgAb levels were found to be independently associated with an increased rate of cesarean hysterectomy and massive blood transfusion in AIP cases (OR: 3.7, 95% CI: 1.4-9.8; p = .01, OR: 1.8, 95% CI: 1.1-3.1; p = .03 and OR: 2.6, 95% CI: 1.0-6.5; p = .05, OR: 2.2, 95% CI: 1.1-4.1 p = .02). Decreased TSH and TgAb serum levels were also found to be independently associated with adverse perinatal outcomes in AIP cases (OR: 3.4, 95% CI: 1.3-11.0; p = .01 and OR: 1.978, 95% CI: 2-3.6; p = .03).

CONCLUSION

Decreased serum TSH and TgAb levels, and previous history of cesarean section were all found to be significantly associated with AIP in cases with PPT. We suggest that maternal serum TSH and TgAb levels can provide additional contribution to obstetric Doppler ultrasound in the diagnosis of AIP and thus can reduce the risks of unplanned cesarean hysterectomy in cases with PPT.

Association Between Overt Hyperthyroidism and Risk of Sexual Dysfunction in Both Sexes: A Systematic Review and Meta-Analysis

BACKGROUND

Numerous studies have shown the detrimental effects of overt hyperthyroidism on sexual functioning but a quantitative result has not yet been synthesized.

AIM

To conduct a systematic review and meta-analysis that quantifies the association between overt hyperthyroidism and the risk of sexual dysfunction (SD).

METHODS

A meta-analysis of studies in the literature published prior to February 1, 2020, from 4 electronic databases (MEDLINE, Embase, Cochrane Library databases, and PsychINFO) was conducted. All analyses were performed using the random-effects model comparing individuals with and without overt hyperthyroidism.

OUTCOMES

The strength of the association between overt hyperthyroidism and risk of SD was quantified by calculating the relative risk (RR) and the standard mean difierences with 95% CI. The quality of evidence for the reported outcome was based on the Grading of Recommendations Assessment, Development, and Evaluation approach.

RESULTS

Of 571 publications, a total of 7 studies involving 323,257 individuals were included. Synthetic results from 7 eligible studies indicated that overt hyperthyroidism led to significant SD in both sexes (pooled RR = 2.59, 95% CI: 1.3-5.17, P = .007; heterogeneity: I² = 98.8%, P < .001). When we analyzed the data of men and women independently, the pooled results consistently showed that men and women with overt hyperthyroidism were at over 2-fold higher risk of SD than the general populations (RR for males = 2.59, 95% CI: 1.03-6.52, P = .044; RR for females = 2.51, 95% CI: 1.47-4.28, P = .001). Combined standard mean diffierences from those studies providing the Female Sexual Function Index (FSFI) suggested that women with overt hyperthyroidism were associated with a significantly lower FSFI value in FSFI total scores, subscale sexual arousal, lubrication, orgasm, and satisfaction domain (all P < .05). The overall quality of evidence in our study was considered to be moderate.

CLINICAL IMPLICATIONS

Clinicians should know the detrimental effects of overt hyperthyroidism on sexual functioning in clinical practice. Measurement of thyroid hormones should be included in the assessment of patients presenting with SD when they show symptoms of clinical hyperthyroidism.

STRENGTHS & LIMITATIONS

This is the first meta-analysis quantifying the relationship between overt hyperthyroidism and the risks of SD. However, the combined results were derived from limited retrospective studies along with substantial heterogeneities.

CONCLUSION

Our study has confirmed the potentially devastating sexual health consequences caused by overt hyperthyroidism. However, additional rigorous studies with sizable samples are still needed to better elucidate this evidence. Pan Y, Xie Q, Zhang Z, et al. Association Between Overt Hyperthyroidism and Risk of Sexual Dysfunction in Both Sexes: A Systematic Review and Meta-Analysis. J Sex Med 2020;17:2198-2207.

Graves' hyperthyroidism in pregnancy

PURPOSE OF REVIEW

Graves' hyperthyroidism is associated with significant obstetric, maternal, fetal, and neonatal complications. Early diagnosis and an understanding of the management of Graves' hyperthyroidism in pregnancy can help to prevent these complications. Antithyroid drugs (ATD) should be avoided in early pregnancy, given their association with congenital malformations.

RECENT FINDINGS

TSH-receptor antibodies (TRAb) are integral in the management of Graves' hyperthyroidism in pregnancy and in the preconception period. TRAb are indicative of the current activity of Graves' hyperthyroidism and the likelihood of relapse. Furthermore, TRAb predicts the risk of fetal and neonatal hyperthyroidism.The incidence of congenital malformations is roughly the same for propylthiouracil (PTU) and methimazole (MMZ). Exposure to both ATDs in early pregnancy has been associated with increased incidence of congenital malformations compared with exposure to either ATD alone.

SUMMARY

The goal of the physician is maintaining euthyroidism throughout pregnancy and delivery of a healthy, euthyroid baby. An understanding of the natural progression of Graves' hyperthyroidism in pregnancy and the proper utilization of TRAb enables the physician to minimize the risks associated with Graves' hyperthyroidism and side effects of ATDs unique to pregnancy. The physician should prioritize preconception counseling in women with Graves' hyperthyroidism in order to avoid hyperthyroidism and having to use ATDs in pregnancy.