Thyroid testing and management of hypothyroidism during pregnancy: a population-based study

Novel Associations Between Mid-Pregnancy Cardiovascular Biomarkers and Preeclampsia: An Explorative Nested Case-Control Study

Prediction of women at high risk of preeclampsia is important for prevention and increased surveillance of the disease. Current prediction models need improvement, particularly with regard to late-onset preeclampsia. Preeclampsia shares pathophysiological entities with cardiovascular disease; thus, cardiovascular biomarkers may contribute to improving prediction models. In this nested case-control study, we explored the predictive importance of mid-pregnancy cardiovascular biomarkers for subsequent preeclampsia. We included healthy women with singleton pregnancies who had donated blood in mid-pregnancy (~ 18 weeks' gestation). Cases were women with subsequent preeclampsia (n = 296, 10% of whom had early-onset preeclampsia [< 34 weeks]). Controls were women who had healthy pregnancies (n = 333). We collected data on maternal, pregnancy, and infant characteristics from medical records. We used the Olink cardiovascular II panel immunoassay to measure 92 biomarkers in the mid-pregnancy plasma samples. The Boruta algorithm was used to determine the predictive importance of the investigated biomarkers and first-trimester pregnancy characteristics for the development of preeclampsia. The following biomarkers had confirmed associations with early-onset preeclampsia (in descending order of importance): placental growth factor (PlGF), matrix metalloproteinase (MMP-12), lectin-like oxidized LDL receptor 1, carcinoembryonic antigen-related cell adhesion molecule 8, serine protease 27, pro-interleukin-16, and poly (ADP-ribose) polymerase 1. The biomarkers that were associated with late-onset preeclampsia were BNP, MMP-12, alpha-L-iduronidase (IDUA), PlGF, low-affinity immunoglobulin gamma Fc region receptor II-b, and T cell surface glycoprotein. Our results suggest that MMP-12 is a promising novel preeclampsia biomarker. Moreover, BNP and IDUA may be of value in enhancing prediction of late-onset preeclampsia.

Biomarkers associated with cardiovascular disease in women with spontaneous preterm birth: A case-control study

INTRODUCTION

Women with spontaneous preterm birth have an increased risk of cardiovascular disease later in life. Studies suggest potential pathophysiological mechanisms in common, but whether these could be identified by measurement of soluble circulating protein biomarkers in women with spontaneous preterm birth is unknown. The aim of this study was to determine if protein biomarkers associated with cardiovascular disease distinguish women with spontaneous preterm birth from healthy controls, both at pregnancy and at follow up.

MATERIAL AND METHODS

Study participants were identified in the population-based Uppsala biobank of pregnant women in Sweden, where plasma samples were collected in mid-pregnancy. In a first screening phase, we identified participants who subsequently experienced spontaneous preterm birth (<37 weeks) in the index pregnancy (N = 13) and controls (N = 6). In these samples, differences in protein expression were examined by comparative mass spectrometry. In a second validation phase, we invited 100 cases with previous spontaneous preterm birth in the index pregnancy and 100 controls (matched for age, body mass index, and year of delivery) from the same source population, to a follow-up visit 4-15 years after pregnancy. At follow up, we collected plasma samples and data on cardiovascular risk factors. We measured concentrations of selected biomarkers identified in the screening phase, as well as lipid profiles in samples both from pregnancy (biobank) and follow up.

CLINICALTRIALS

gov registration NCT05693285.

RESULTS

In the screening phase, fibrinogen, cadherin-5, complement C5, factor XII, plasma kallikrein, apolipoprotein M, and vitamin D-binding protein differed significantly at pregnancy. In the validation phase, 65 women agreed to participate (35 cases and 30 controls), with a median follow-up time of 11.8 years since pregnancy. The concentration of fibrinogen (p = 0.02) and triglycerides (p = 0.03) were slightly higher in cases compared with matched controls at follow up.

CONCLUSIONS

Compared with women without preterm birth, those with spontaneous preterm birth had slightly higher concentrations of fibrinogen, both at mid-pregnancy and a decade after pregnancy. Additionally, we found slightly higher concentration of triglycerides at follow up in women with previous spontaneous preterm birth. The relevance of this finding is uncertain but might indicate potential pathophysiological mechanisms in common between spontaneous preterm birth and cardiovascular disease.

Under and overtreatment with thyroid hormone replacement during pregnancy

PURPOSE OF REVIEW

Among pregnant women on thyroid hormone replacement therapy undertreatment is common, while overtreatment is rare. Both deficient and excessive maternal thyroid hormone have been related to adverse maternofetal and long-term offspring outcomes, although studies' results are inconsistent. This review aims to discuss recent evidence regarding the effects of under- and overtreatment with thyroid hormone replacement during pregnancy and how current practices could be improved.

RECENT FINDINGS

Whether or not thyroid hormone therapy needs to be initiated for maternal subclinical hypothyroidism remains unclear, but recent meta-analyses have confirmed associations between adverse maternal, neonatal, and offspring outcomes in both overt and subclinical hypothyroidism. Subclinical hyperthyroidism in pregnancy is related to fewer adverse outcomes. Current adherence to levothyroxine during pregnancy and medication counseling by healthcare providers are suboptimal.

SUMMARY

Undertreatment of maternal hypothyroidism may increase risks for adverse maternofetal and offspring effects more than overtreatment does. If thyroid hormone replacement therapy is indicated and initiated in pregnancy, frequent thyroid function monitoring is required to avoid under- or overtreatment. Effective communication between clinicians and patients is imperative to increase medication adherence.

Thyroid Laboratory Testing and Management in Women on Thyroid Replacement Before Pregnancy and Associated Pregnancy Outcomes

Background: Women with hypothyroidism before pregnancy often require an increase in their levothyroxine dosage to maintain a euthyroid state during pregnancy. The objectives of this study were to investigate: (i) the frequency and distribution of thyrotropin (TSH) testing and levothyroxine dosage adjustment by gestational age, (ii) the magnitude of levothyroxine increase by the underlying etiology of hypothyroidism, and (iii) the relationship of overtreatment or undertreatment during pregnancy with adverse pregnancy outcomes among women using thyroid replacement before pregnancy. Methods: A retrospective cohort study of pregnancies in women on thyroid replacement before pregnancy in Alberta, Canada, was performed. Women using thyroid replacement anytime during the two years before pregnancy who delivered between October 2014 and September 2017 were included. Delivery records, physician billing, and laboratory and pharmacy administrative data were linked. Outcomes included characteristics of TSH testing, levothyroxine dosing, and pregnancy outcomes. The frequency and gestational timing of TSH testing and levothyroxine adjustments were calculated. Multiple logistic regression was used to test whether pregnancies with TSH <0.10 mIU/L (overtreatment) or TSH ≥10.00 mIU/L (undertreatment) compared with control pregnancies (TSH 0.10-4.00 mIU/L) were associated with adverse pregnancy and neonatal outcomes. Results: Of the 10,680 deliveries, 8774 (82.2%) underwent TSH testing at least once during pregnancy, at a median gestational age of six weeks. An adjustment of levothyroxine dosage was made for 4321 (43.7%) during pregnancy. TSH in pregnancy below 0.10 mIU/L increased the odds of preterm delivery when compared with control pregnancies (adjusted odds ratio, 2.14 [95% confidence interval 1.51-2.78]). TSH ≥10.00 mIU/L during pregnancy was not associated with any adverse pregnancy or neonatal outcomes in the multivariable analysis. Conclusions: Although most women on thyroid replacement before conception had TSH measured at some point during pregnancy, it is concerning that 17.8% did not. Levothyroxine overtreatment in pregnancy was associated with preterm delivery. These findings suggest that clinicians should be careful to avoid overtreatment with levothyroxine in pregnancy.

Thyroid function control among pregnant women following a therapeutic thyroidectomy

OBJECTIVES

The aim of this study was to assess the extent of thyroid function control among pregnant women who had previously undergone a therapeutic thyroidectomy.

DESIGN

Retrospective cohort study.

SETTING

The largest health maintenance organization in Israel.

PARTICIPANTS

All female patients who were pregnant between May, 2001 and September, 2012 and had a medical history of thyroid surgery.

MAIN OUTCOME MEASURE

The thyroid-stimulating hormone (TSH) levels throughout the pregnancy were compared to recommended trimestral values. A multivariate analysis was performed to determine risk factors for not attaining TSH recommended range.

RESULTS

A total of 477 females with a history of thyroid surgery had given 701 births during the study period. Forty-three percent (n = 203), had thyroidal malignancy. Nearly half of the women underwent total thyroidectomy (43.4%, n = 207). The women's TSH values were within the recommended range in only 60% (n = 350) of the pregnancies during the first trimester (0.1-2.5 mIU/L), in 61% (n = 335) during the second trimester (0.2-3 mIU/L), and in 70% (n = 338) during the third trimester (0.3-3 mIU/L). In multivariate analysis, women that underwent a total thyroidectomy due to a benign thyroid disease, were at the highest risk for not attaining target TSH levels.

CONCLUSIONS

This very large cohort of pregnant women with a past history of thyroid surgery demonstrated a significant percentage of pregnancies with TSH values above the recommended range. Women that underwent a total thyroidectomy due to benign thyroid disease were at the highest risk for gestational hypothyroidism.

Thyroid function abnormalities and thyroid autoantibodies in Danish pregnant women

OBJECTIVE

Abnormal thyroid function in pregnant women is a matter of concern. Knowledge on the occurrence of known and unidentified thyroid function abnormalities in a large unselected cohort of pregnant women is warranted as part of the debate on benefits and risks of routine testing.

DESIGN

Cohort study.

PARTICIPANTS

A total of 14 323 pregnant women in the North Denmark Region, who had a blood sample drawn as part of the prenatal screening program in early pregnancy (2011-2015).

MEASUREMENTS

TSH, free thyroxine, thyroid peroxidase and thyroglobulin antibodies were measured in the stored blood samples using an automatic immunoassay (ADVIA Centaur XPT, Siemens Healthineers). Cohort-, method- and week-specific reference ranges were used for classification of maternal thyroid function, and a cut-off of 60 U/mL was used for thyroid autoantibodies. Information in Danish nationwide registers was used to identify diagnosed and treated maternal thyroid disease.

RESULTS

Overall, 15.2% had thyroid function abnormalities in the early pregnancy and 14.9% were thyroid peroxidase and/or thyroglobulin antibody positive. Among women with known thyroid disease (n = 365), the frequency of abnormal thyroid function was 45.7%, and 62.8% in women (n = 172) who received current treatment in the pregnancy. When maternal thyroid disease was diagnosed in the years following pregnancy (n = 313), 46.7% had abnormal thyroid function and 54.3% were thyroid peroxidase and/or thyroglobulin antibody positive in the early pregnancy.

CONCLUSION

Thyroid function abnormalities and thyroid autoantibodies were common in Danish pregnant women, particularly in women with known or later diagnosed thyroid disease, which raises concern about inadequately treated and unidentified abnormal thyroid function.

Adherence to Swedish national pregnancy dating guidelines and management of discrepancies between pregnancy dating methods: a survey study

Background

Swedish national guidelines for pregnancy dating were published in 2010. Follow-up is needed to assess adherence and to identify whether any clinical topics are not covered in the guidelines.

Methods

All units in Sweden that performed ultrasound-based pregnancy dating were asked to complete a web-based questionnaire comprising multiple-response questions and commentary fields. Information was collected regarding baseline information, current and previous clinical practice, and management of discrepancies between last-menstrual-period- and ultrasound-based methods for pregnancy dating.

Results

The response rate was 79%. Half of the units offered first-trimester ultrasound to all pregnant women. However, contrary to the guidelines, the crown–rump length was not used for ultrasound-based pregnancy dating in most units. Instead, ultrasound-based pregnancy dating was performed only if the biparietal diameter was between 21 and 55 mm. Management of discrepancies between methods for pregnancy dating varied widely.

Conclusions

The units reported high adherence to national guidelines, except for early pregnancy dating, for which many units followed unwritten or informal guidelines. The management of discrepancies between last-menstrual-period-based and ultrasound-based estimated day of delivery varied widely. These findings emphasize the need for regular updating of national written guidelines and efforts to improve their implementation in all units.

Diagnosis, treatment, and management of gestational hypothyroidism. The TIROGEST study

INTRODUCTION

There is no agreement on the procedures to be used for diagnosis and treatment of gestational thyroid dysfunction. Controversy still exists on the normal range of thyroid-stimulating hormone (TSH) levels and use of gestational hypothyroidism (GH) screening. The aim of this study was to assess diagnosis and treatment of thyroid dysfunction during pregnancy in a group of Spanish hospitals.

STUDY DESIGN

This was a retrospective, multicenter study in pregnant females with GH attending Spanish healthcare centers from March 2013 to July 2014. Variables analyzed included diagnosis criteria for GH (availability of universal screening for gestational thyroid disorders and TSH reference values (RVs) by trimester of pregnancy): risk factors for GH, iodine intake from food or supplementation, gestational age (at diagnosis/treatment) and l-thyroxine treatment.

RESULTS

Fourteen centers participated in the study. Universal screening was performed in only half of the centers, and only 14% had their own TSH RVs. Overall, 257 pregnant women were enrolled, 53.7% with hypothyroidism (HT) diagnosed before pregnancy (pre-GH) and 46.3% with HT diagnosed during pregnancy (intra-GH). A comparison of intra-GH and pre-GH women showed that intra-GH women made their first visit later (59.7% vs. 75.4% respectively before week 12, p=0.007) and had more frequently high TSH levels (>2.5μIU/ml) during the first trimester (94.4% vs. 67.0% respectively, p<0.001).

CONCLUSIONS

Our results suggest that GH may be underdiagnosed or inadequately diagnosed in most healthcare centers. These findings suggest the need of improving the current practice in Spain.

Elevated prenatal anti-Müllerian hormone reprograms the fetus and induces polycystic ovary syndrome in adulthood

Polycystic ovary syndrome (PCOS) is the main cause of female infertility worldwide and corresponds with a high degree of comorbidities and economic burden. How PCOS is passed on from one generation to the next is not clear, but it may be a developmental condition. Most women with PCOS exhibit higher levels of circulating luteinizing hormone, suggestive of heightened gonadotropin-releasing hormone (GnRH) release, and Anti-Müllerian Hormone (AMH) as compared to healthy women. Excess AMH in utero may affect the development of the female fetus. However, as AMH levels drop during pregnancy in women with normal fertility it was unclear if their levels were also elevated in pregnant women with PCOS. Here, we measured AMH in a cohort of pregnant women with PCOS and control women and found that AMH is significantly more elevated in the former group versus the latter. To determine if the elevation of AMH during pregnancy in women with PCOS is a bystander effect or a driver of the condition in the offspring, we modelled our clinical findings by treating pregnant mice with AMH and followed the neuroendocrine phenotype of their female progeny postnatally. This treatment resulted in maternal neuroendocrine-driven testosterone excess and diminished placental metabolism of testosterone to estradiol, resulting in a masculinization of the exposed female fetus and a PCOS-like reproductive and neuroendocrine phenotype in adulthood. We found that the affected females had persistently hyperactivated GnRH neurons and that GnRH antagonist treatment in the adult female offspring restored their neuroendocrine phenotype to a normal state. These findings highlight a critical role for excess prenatal AMH exposure and subsequent aberrant GnRH receptor signaling in the neuroendocrine dysfunctions of PCOS, while offering a new potential therapeutic avenue to treat the condition during adulthood.

Thyroid hormone regulates protease expression and activation of Notch signaling in implantation and embryo development

A clinical association between thyroid dysfunction and pregnancy complications has been extensively reported; however, the molecular mechanisms through which TH might regulate key events of pregnancy have not been elucidated yet. In this respect, we performed in vivo studies in MMI-induced hypothyroid pregnant mice, evaluating the effect of hypothyroidism on the number of implantation sites, developing embryos/resorptions and pups per litter, at 4.5, 10.5, 18.5 days post-coitum (dpc) and at birth. We also studied the expression of major molecules involved in implantation and placentation, such as the proteases ISPs, MMPs, TIMPs and Notch pathway-related genes. Our results demonstrate that hypothyroidism may have a dual effect on pregnancy, by initially influencing implantation and by regulating placental development at later stages of gestation. To further elucidate the role of TH in implantation, we performed in vitro studies by culturing 3.5 dpc blastocysts in the presence of TH, with or without endometrial cells used as the feeder layer, and studied their ability to undergo hatching and outgrowth. We observed that, in the presence of endometrial feeder cells, TH is able to anticipate blastocyst hatching by upregulating the expression of blastocyst-produced ISPs, and to enhance blastocyst outgrowth by upregulating endometrial ISPs and MMPs. These results clearly indicate that TH is involved in the bidirectional crosstalk between the competent blastocyst and the receptive endometrium at the time of implantation.

Prepregnancy Hypothyroidism versus Gestational Hypothyroidism: A Comparative Study

INTRODUCTION

Hypothyroidism managed inadequately in pregnancy may have grave outcomes for both mother and baby. Understanding pregnancy outcomes in our country with low awareness about thyroid diseases is important.

OBJECTIVES

The objectives of the study were to evaluate demographic features and biochemical parameters in patients with prepregnancy hypothyroidism versus patients diagnosed to have primary hypothyroidism during pregnancy and to assess pregnancy outcomes.

STUDY DESIGN

Prospective design.

MATERIALS AND METHODS

The study was conducted in a tertiary care center in Bengaluru for 2 years. The patients were divided into two groups - Group I: Prepregnancy hypothyroidism and Group II: Hypothyroid during pregnancy. They were further staged according to ESI guidelines as subclinical or overt hypothyroidism.

STATISTICAL ANALYSIS

Chi-square and Mann-Whitney test.

RESULTS

A total of 452 pregnant women with hypothyroidism were analyzed. The data of 371 delivered pregnancies were available. Group I and II had 196 (43.36%) and 256 (56.64%) patients, respectively. Age at presentation (years) was 27.09 ± 4.19 in Group I versus 25.74 ± 4.29 in Group II (P = 0.003); gestational age (weeks) was 9.04 ± 5.41 in Group I versus 13.81 ± 9.12 in Group II (P = 0.000). There was one case of congenital hypothyroidism in baby in each group. Mean birth weight was 2.90 ± 0.39 kg in Group I versus 2.88 ± 0.36 kg in Group II; P = 0.608. There were four abortions in Group I versus ten in Group II (P = 0.231), 104 cesarean sections in Group I compared to 133 in Group II; (P = 0.382). There was no difference in number of cesarean sections, abortions and low birth weight babies between overt and subclinical hypothyroidism subgroups.

CONCLUSIONS

Group I patients presented earlier for testing suggesting awareness was good in this group. There was no difference in pregnancy outcome between the two groups. Overt versus subclinical status did not have any different effects on pregnancy outcomes in any group.

Allopregnanolone levels and depressive symptoms during pregnancy in relation to single nucleotide polymorphisms in the allopregnanolone synthesis pathway

Allopregnanolone, a neurosteroid whose levels rise throughout gestation, putatively stabilizes antenatal mood. The present study aimed to investigate associations of plasma allopregnanolone to antenatal depressive symptoms, as well as to genetic and obstetric factors. Allopregnanolone plasma levels from 284 pregnant women were measured around gestational week 18. Haplotype tag single nucleotide polymorphisms in the aldo-keto reductase family 1, members C2 and C4 (AKR1C2, AKR1C4), and steroid 5 alpha-reductase 1 and 2 (SRD5A1, and SRD5A2) genes were genotyped in a larger sample of pregnant women (n=1351). The Edinburgh Postnatal Depression Scale (EPDS) was administered via web-questionnaires in gestational weeks 17 and 32. Demographic and obstetric data was retrieved from web-questionnaires and medical records. There was no association between allopregnanolone levels and depressive symptoms. Furthermore, no associations between allopregnanolone level and synthesis pathway genotypes were found after accounting for multiple comparisons. However, exploratory analyses suggested that the women who were homozygous for the minor allele of the AKR1C2 polymorphism rs1937863 had nominally lower allopregnanolone levels and lower depression scores in gestational week 17, but also the highest increase in depression scores between week 17 and 32. Additionally, higher body mass index was associated with lower allopregnanolone levels. The results do not support second trimester plasma allopregnanolone as a mood stabilizing factor. However, we speculate that AKR1C2 variation may alter the susceptibility to depressive symptoms through effects on central allopregnanolone synthesis. Another implication of this study is that the relationship between neuroactive steroids and obesity in pregnancy deserves to be investigated.

Early Pregnancy Thyroid Function Test Abnormalities in Biobank Sera from Women Clinically Diagnosed with Thyroid Dysfunction Before or After Pregnancy

BACKGROUND

Maternal thyroid disease may complicate pregnancy. A high frequency of abnormal thyroid function test results in pregnant women with known thyroid disease has been reported, but the frequency of unidentified thyroid dysfunction in women first clinically diagnosed with thyroid disease after a pregnancy is not known.

METHODS

This was a population-based study of pregnant women in the Danish National Birth Cohort (DNBC) who had a blood sample drawn in early pregnancy and terminated the pregnancy with a singleton live-birth in the period between 1997 and 2003. Participants were all women in the DNBC who had a registration of thyroid disease before and/or up to five years after the pregnancy in nationwide health registers (n = 2445) and a 12% random sample of all women in the cohort (n = 7624). Thyrotropin and free thyroxine were measured with an immunoassay in sera stored in the Danish National Biobank. Method- and pregnancy week-specific references ranges were used for classification of thyroid function test abnormalities.

RESULTS

The frequency of abnormal thyroid function in early pregnancy was 12.5% in the random sample and 35.7% among women clinically diagnosed with thyroid disease before or after blood sampling (55.7% among women on current treatment). One third of women clinically diagnosed with thyroid disease after blood sampling had unidentified thyroid dysfunction in the early pregnancy blood sample (most frequently [52.0%] unidentified hypothyroidism in women with a later diagnosis of hypothyroidism).

CONCLUSIONS

More than 50% of Danish pregnant women on current treatment for thyroid disease had thyrotropin and/or free thyroxine outside the week-specific reference ranges, and the frequency of unidentified early pregnancy thyroid dysfunction in women clinically diagnosed after the pregnancy was also high.

Effects of increasing levothyroxine on pregnancy outcomes in women with uncontrolled hypothyroidism

OBJECTIVE

Uncontrolled hypothyroidism has been associated with an increased risk of adverse pregnancy outcomes. We aimed to assess the effectiveness of increasing levothyroxine (LT4) dose on reducing the risk of adverse outcomes for pregnant women with TSH level greater than the recommended 1st trimester limit.

DESIGN, PATIENTS, MEASUREMENTS

We reviewed the electronic medical records of pregnant women evaluated from January 2011 to December 2013, who had history of LT4-treated hypothyroidism and were found to have TSH > 2·5 mIU/l in 1st trimester. Women were divided into two groups: group A - LT4 dose was increased within two weeks from the TSH test, group B - LT4 dose remained stable. We compared the frequency of pregnancy loss (primary outcome) and other prespecified pregnancy-related adverse outcomes between groups.

RESULTS

There were 85 women in group A (median TSH: 5·0, interquartile range 3·8-6·8 mIU/l) and 11 women in group B (median TSH: 4·5, interquartile range 3·2-4·9 mIU/l). The groups were not different in baseline clinical and socioeconomic characteristics. The mean interval between TSH test and LT4 dose increase was 4·5 (SD 4·6) days. Pregnancy loss was significantly lower in group A (2/85, 2·4%) vs group B (4/11, 36·4%) (P = 0·001). Other pregnancy-related adverse outcomes were similar between groups.

CONCLUSIONS

Increasing LT4 dose for women with uncontrolled hypothyroidism in the 1st trimester of pregnancy was associated with a decreased risk of pregnancy loss. Given the limitations of our study, this association awaits further confirmation from larger studies.

Hypothyroidism and pregnancy loss: comparison with hyperthyroidism and diabetes in a Danish population-based study

BACKGROUND

Hypothyroidism is a common endocrine disease. The frequency of pregnancy loss in women with known hypothyroidism as opposed to women with a later diagnosis of hypothyroidism has not been evaluated and compared with other common endocrine diseases.

DESIGN

Population-based cohort study using Danish nationwide registers.

PARTICIPANTS

All pregnancies in Denmark, 1997-2008, resulting in live birth (n = 732 533), spontaneous abortion (n = 112 487) or stillbirth (n = 2937) were identified together with information on maternal hypothyroidism, hyperthyroidism and diabetes.

METHODS

Cox model was used to estimate adjusted hazard ratio (aHR) with 95% confidence interval (95%CI) for spontaneous abortion and stillbirth, reference: no hypo- or hyperthyroidism or diabetes (n = 824 310).

RESULTS

We identified 4951 pregnancies where maternal hypothyroidism was diagnosed before the pregnancy (group 1) and 2464 pregnancies where maternal hypothyroidism was diagnosed in the 2-year period after the pregnancy (group 2). In group 1, 825 pregnancies (16·7%) resulted in spontaneous abortion which was more frequent than in nonexposed (13·2%), (aHR 1·19 (95%CI 1·12-1·27)), and of the same magnitude as in hyperthyroidism (17·2%, P = 0·5) and diabetes (17·5%, P = 0·2) diagnosed before the pregnancy. In group 2, the frequency was 12·2% (aHR 0·92 (0·84-1·02)). In group 2, 16 pregnancies (0·65%) resulted in stillbirth which was more frequent than in nonexposed (0·36%), (aHR 1·81 (1·11-2·97)), of the same magnitude as in hyperthyroidism (0·82%, P = 0·5) and less frequent than in diabetes (2·9%, P < 0·001) diagnosed after the pregnancy. In group 1, the frequency was 0·40% (aHR 1·11 (0·68-1·82)).

CONCLUSIONS

Hypothyroidism increased the risk of both early and late pregnancy loss as did hyperthyroidism and in particular diabetes. We hypothesize that undetected or insufficiently treated maternal disease in the pregnancy may be of causal importance.

Medication adherence among pregnant women with hypothyroidism-missed opportunities to improve reproductive health? A cross-sectional, web-based study

OBJECTIVE

To evaluate patterns of and factors associated with a lack of pharmacotherapy as well as low adherence to treatment of hypothyroidism in pregnancy.

METHODS

This multinational, cross-sectional, internet-based study recruited pregnant woman in 18 countries. Data about women's socio-demographic and medical characteristics, medication adherence (8-item Morisky Medication Adherence Scale), beliefs about medication (Beliefs about Medicine Questionnaire), and personality traits (Big Five Personality Trait questionnaire) were collected via an online questionnaire.

RESULTS

229 of 5095 women had hypothyroidism during pregnancy; of these, 93% reported hypothyroidism pharmacotherapy. Adherence was low among 17% (95% CI: 12.5-22.5%) of medicated women, whilst it was moderate and high among 44% and 39%, respectively. Not using folic acid and not living in a stable relationship were associated with an increased likelihood for untreated hypothyroidism. Younger maternal age and not using folic acid in pregnancy were factors significantly associated with low adherence. Conscientiousness and the perception that the benefit of pharmacotherapy outweighed the risks were associated with higher levels of adherence.

CONCLUSION

There is room for improvement of adherence to hypothyroidism treatment in pregnancy.

PRACTICE IMPLICATIONS

Counselling of women with hypothyroidism in pregnancy should include a proper risk communication and information framing, to ameliorate maternal and foetal health.

Maternal thyroid disease in the Danish National Birth Cohort: prevalence and risk factors

OBJECTIVE

Thyroid disorders are common in women of reproductive age, but the exact burden of disease before, during and after a pregnancy is not clear. We describe the prevalence of thyroid disease in women enrolled in the Danish National Birth Cohort (DNBC) and investigate some of its risk factors.

DESIGN

Population-based study within the DNBC, which included 101,032 pregnancies (1997-2003).

METHODS

We studied women enrolled in the DNBC who gave birth to a live-born child. Information on maternal thyroid disease (hyperthyroidism, hypothyroidism, benign goiter/nodules, thyroid cancer, and other) before, during and up to 5 years after the woman's first pregnancy in the cohort was obtained from self-report (telephone interview in median gestational week 17) and from nationwide registers on hospital diagnosis of thyroid disease/thyroid surgery (from 1977) and prescriptions of thyroid drugs (from 1995).

RESULTS

Of the 77,445 women studied, 3018 (3.9%) were identified with an onset of thyroid disease before (2.0%), during (0.1%) or in the 5-year period after the pregnancy (1.8%). During the pregnancy, 153 (0.2%) women received antithyroid drugs and 365 (0.5%) received thyroid hormone for hypothyroidism (83 after previous hyperthyroidism, 42 after previous surgery for benign goiter/nodules or thyroid cancer). Significant risk factors for maternal thyroid disease were age, parity, origin, iodine intake, smoking, alcohol, and BMI.

CONCLUSIONS

Around 4% of Danish pregnant women had either a history of thyroid disease or thyroid disease during pregnancy or were diagnosed with thyroid disease for the first-time in the years following a pregnancy. The spectrum of thyroid disease was influenced by demographic and environmental factors.

Foetal programming by maternal thyroid disease

Foetal programming is an emerging concept that links a wide range of exposures during foetal life to later development of disease. Thyroid disorders are common in women of reproductive age, and careful management of pregnant women suffering from thyroid disease is important considering the crucial role of thyroid hormones during early brain development. It is possible that maternal thyroid dysfunction in pregnancy may lead to structural and/or functional changes during foetal brain development. Such an effect could later predispose the offspring to an increased risk of neurologic or psychiatric disease. We recently observed that children born to mothers with thyroid dysfunction had an increased risk of developing seizure disorders, autism spectrum disorders, attention-deficit hyperactivity disorders and psychiatric disease in adolescence and young adulthood. In the review, we discuss the concept of potential foetal programming by maternal thyroid disease.

Treatment with serotonin reuptake inhibitors during pregnancy is associated with elevated corticotropin-releasing hormone levels

Treatment with serotonin reuptake inhibitors (SSRI) has been associated with an increased risk of preterm birth, but causality remains unclear. While placental CRH production is correlated with gestational length and preterm birth, it has been difficult to establish if psychological stress or mental health problems are associated with increased CRH levels. This study compared second trimester CRH serum concentrations in pregnant women on SSRI treatment (n=207) with untreated depressed women (n=56) and controls (n=609). A secondary aim was to investigate the combined effect of SSRI treatment and CRH levels on gestational length and risk for preterm birth. Women on SSRI treatment had significantly higher second trimester CRH levels than controls, and untreated depressed women. CRH levels and SSRI treatment were independently associated with shorter gestational length. The combined effect of SSRI treatment and high CRH levels yielded the highest risk estimate for preterm birth. SSRI treatment during pregnancy is associated with increased CRH levels. However, the elevated risk for preterm birth in SSRI users appear not to be mediated by increased placental CRH production, instead CRH appear as an independent risk factor for shorter gestational length and preterm birth.

Pregnancy outcomes and relationship to treatment adequacy in women treated early for congenital hypothyroidism: a longitudinal population-based study

CONTEXT

Untreated hypothyroidism is associated with a higher risk of adverse obstetric and neonatal outcomes. Pregnancy complications have yet to be evaluated in patients treated early for congenital hypothyroidism (CH).

OBJECTIVE

This study aimed to investigate pregnancy outcomes and their determinants in a population-based registry of young adult women with CH.

SETTING AND DESIGN

In total, 1748 subjects were diagnosed with CH in the first 10 years after the introduction of neonatal screening in France; 1158 of these subjects completed a questionnaire on fecundity at a mean age of 25.3 years. We analyzed all declared singleton pregnancies ending after greater than 22 weeks of gestation before the initial survey (n = 207 pregnancies) and in the 3 years following the initial survey (prospective study, n = 174 pregnancies). The reference group comprised 7245 subjects from the French National Perinatal Survey.

MAIN OUTCOME MEASURES

Pregnancy outcomes. Serum TSH concentrations and thyroid hormone requirements.

RESULTS

In both the overall and prospective analyses, CH was associated with gestational hypertension, emergency cesarean delivery, induced labor for vaginal delivery, and prematurity. For the prospective population with CH, the adjusted odds ratios (aOR) (95% confidence interval [CI]) were 2.19 (1.26-3.81), 1.88 (1.17-3.02), 1.58 (1.12-2.24), and 1.85 (1.06-3.25), respectively. TSH concentrations at least 10 mIU/l during the first 3 or 6 months of pregnancy were associated with a higher risk of preterm delivery (aOR, 5.6; 95% CI, 1.6-20.0) and fetal macrosomia (aOR, 4.5; 95% CI, 1.03-20.1), respectively, whereas no such relationship was observed for TSH concentrations of 5.0-9.9 mIU/l.

CONCLUSION

CH may result in adverse pregnancy outcomes. These nationwide data suggest that better thyroid disease management is required, particularly during the first two trimesters of pregnancy, together with vigilant monitoring.

[Impact of thyroid function on fertility]

Until recently, anovulation or recurrent miscarriages were the only situations for screening a thyroid dysfunction in an infertile patient. Recent U.S. guidelines published in 2011 identify infertile women as being at risk for thyroid dysfunction. This paper proposes, on the occasion of the new recommendations, a review of the literature data on the known impact of thyroid dysfunction on fertility, on the first trimester of pregnancy and on the way to treat them.

Congenital hypothyroidism: a clinical update of long-term outcome in young adults

Congenital hypothyroidism (CH) is the most common congenital endocrine disorder. The early treatment of CH patients has successfully improved the prognosis and management of this disorder. Optimal treatment and management throughout the patient's life, beginning in the neonatal period, are required to ensure long-term health. Affected patients should be offered assessments of associated medical conditions and provided with accurate information about their condition throughout their lives, but particularly during the transition from pediatric to adult services. This review provides a summary of current knowledge about the long-term outcomes of these patients and appropriate management into early adulthood. We carried out a systematic search of the Medline database to identify relevant articles. Despite major improvements in prognosis, the impact of CH is clearly not uniform, and management should take into account a broader range of relevant indicators, including CH severity, associated comorbid conditions and the adequacy of treatment during childhood and adulthood. The early diagnosis and management of associated medical conditions, and better educational strategies to improve compliance with treatment, should improve the long-term prognosis. Further studies are required to explore changes with aging.

TSH levels and risk of miscarriage in women on long-term levothyroxine: a community-based study

CONTEXT

Thyroid dysfunction is associated with adverse obstetric outcomes, but there is limited information on pregnancy outcomes in women established on levothyroxine.

OBJECTIVE

The objective of the study was to determine the relationship between TSH levels and pregnancy outcomes in levothyroxine-treated women in a large community-based database.

DESIGN

This was a historical cohort analysis.

PATIENTS

Individuals with a first prescription of levothyroxine from 2001 through 2009 (n = 55 501) were identified from the UK General Practice Research Database (population 5 million). Of these, we identified 7978 women of child-bearing age (18-45 y) and 1013 pregnancies in which levothyroxine had been initiated at least 6 months before conception.

MAIN OUTCOME MEASURES

TSH, miscarriage/delivery status, and obstetric outcomes were measured.

RESULTS

Forty-six percent of levothyroxine-treated women aged 18-45 years had a TSH level greater than 2.5 mU/L (recommended upper level in the first trimester). Among pregnant women who had their TSH measured in the first trimester, 62.8% had a TSH level greater than 2.5 mU/L, with 7.4% greater than 10 mU/L. Women with TSH greater than 2.5 mU/L in the first trimester had an increased risk of miscarriage compared with women with TSH 0.2-2.5 mU/L after adjusting for age, year of pregnancy, diabetes, and social class (P = .008). The risk of miscarriage was increased in women with TSH 4.51-10 mU/L [odds ratio (OR) 1.80, 95% confidence interval (CI) 1.03, 3.14)] and TSH greater than 10 mU/L (OR 3.95, 95% CI 1.87, 8.37) but not with TSH 2.51-4.5 mU/L (OR 1.09, 95% CI 0.61, 1.93).

CONCLUSIONS

The majority of levothyroxine-treated women have early gestational TSH levels above the recommended targets (>2.5 mU/L) with a strong risk of miscarriage at levels exceeding 4.5 mU/L. There is an urgent need to improve the adequacy of thyroid hormone replacement in early pregnancy.

Targeted thyroid testing during pregnancy in clinical practice

OBJECTIVE

To evaluate the efficacy of a targeted thyroid testing approach during pregnancy in clinical practice.

METHODS

This is a retrospective cohort study performed within Uppsala County, Sweden. Data were derived from the population-based Uppsala Biobank of Pregnant Women, in which blood samples are collected in conjunction with the routine ultrasound screening in gestational week 17-19. For this study, 5,254 pregnant women with an estimated date of delivery between January 1, 2009, and December 31, 2011, were included. On review of their medical records, women who were tested for thyroid dysfunction during pregnancy in clinical practice were identified (n=891). From the remaining untested women, 1,006 women were randomly selected for analyses of thyrotropin (TSH), free thyroxine levels, and thyroid peroxidase antibodies. Thyroid-stimulating hormone levels in both groups were analyzed with regard to trimester-specific upper reference levels as recommended by the International Endocrine Society Guidelines.

RESULTS

The proportion of trimester-specific TSH elevation was 12.6% in the targeted thyroid testing group and 12.1% in the untested group (P=.8; odds ratio [OR] 1.04, 95% confidence interval [CI] 0.79-1.37). The proportion of overt hypothyroidism was 1.1% and 0.7% in the groups, respectively (P=.4; OR 1.57, 95% CI 0.55-4.45).

CONCLUSIONS

The prevalence of trimester-specific elevated TSH and overt hypothyroidism was equal in targeted thyroid tested and untested women. When implemented in clinical practice, targeted thyroid testing is unsatisfactory. If ongoing studies provide support for treatment of pregnant women with elevated TSH, universal thyroid testing appears the most reasonable approach.

LEVEL OF EVIDENCE

: II.

Psychiatric disease in late adolescence and young adulthood. Foetal programming by maternal hypothyroidism?

OBJECTIVE

Lack of maternal thyroid hormones during foetal brain development may lead to structural abnormalities in the brain. We hypothesized that maternal hypothyroidism during the pregnancy could programme the foetus to development of psychiatric disease later in life.

DESIGN

Danish nationwide register study.

PARTICIPANTS

Singletons live-born 1980-1990.

MEASUREMENTS

Cox proportional hazards model was used to estimate adjusted hazard ratio (aHR) with 95% confidence interval for offspring redemption of ≥2 prescriptions of a psychiatric drug from age 15 to 31 years.

RESULTS

Among 542 100 adolescents and young adults included, altogether 3979 (0·7%) were born to mothers with hypothyroidism registered before 1996. In crude analyses, the use of a psychiatric drug was more frequent in late adolescence and young adulthood when the mother had hypothyroidism (P < 0·001); however, several possible confounders had to be taken into account. For example, mothers with hypothyroidism often also had a psychiatric registration (38·5% vs 27·7%, P < 0·001) and the use of psychiatric drugs changed over time. After adjustment for confounders including birth year, maternal age and maternal psychiatric history, maternal hypothyroidism was associated with an increased risk of having redeemed prescriptions of anxiolytics [aHR 1·23 (1·03-1·48)] and antipsychotics [aHR 1·22 (1·03-1·44)] in late adolescence and young adulthood. For antidepressants, aHR was 1·07 (0·98-1·17).

CONCLUSIONS

The association between maternal hypothyroidism and the use of a psychiatric drug in late adolescence and young adulthood was partly confounded by maternal psychiatric history, but foetal programming by maternal hypothyroidism may be part of the mechanisms leading to the use of anxiolytics and antipsychotics.

Molecular basis of thyrotropin and thyroid hormone action during implantation and early development

BACKGROUND

Implantation and early embryo development are finely regulated processes in which several molecules are involved. Evidence that thyroid hormones (TH: T4 and T3) might be part of this machinery is emerging. An increased demand for TH occurs during gestation, and any alteration in maternal thyroid physiology has significant implications for both maternal and fetal health. Not only overt but also subclinical hypothyroidism is associated with infertility as well as with obstetric complications, including disruptions and disorders of pregnancy, labor, delivery, and troubles in early neonatal life.

METHODS

We searched the PubMed and Google Scholar databases for articles related to TH action on ovary, endometrium, trophoblast maturation and embryo implantation. In addition, articles on the regulation of TH activity at cellular level have been reviewed. The findings are hereby summarized and critically discussed.

RESULTS

TH have been shown to influence endometrial, ovarian and placental physiology. TH receptors (TR) and thyrotropin (thyroid-stimulating hormone: TSH) receptors (TSHR) are widely expressed in the feto-maternal unit during implantation, and both the endometrium and the trophoblast might be influenced by TH either directly or through TH effects on the synthesis and activity of implantation-mediating molecules. Interestingly, due to the multiplicity of mechanisms involved in TH action (e.g. differential expression of TR isoforms, heterodimeric receptor partners, interacting cellular proteins, and regulating enzymes), the TH concentration in blood is not always predictive of their cellular availability and activity at both genomic and nongenomic level.

CONCLUSIONS

In addition to the known role of TH on the hormonal milieu of the ovarian follicle cycle, which is essential for a woman's fertility, evidence is emerging on the importance of TH signaling during implantation and early pregnancy. Based on recent observations, a local action of TH on female reproductive organs and the embryo during implantation appears to be crucial for a successful pregnancy. Furthermore, an imbalance in the spatio-temporal expression of factors involved in TH activity might induce early arrest of pregnancy in women considered as euthyroid, based on their hormonal blood concentration. In conclusion, alterations of the highly regulated local activity of TH may play a crucial, previously underestimated, role in early pregnancy and pregnancy loss. Further studies elucidating this topic should be encouraged.

Attention deficit hyperactivity disorder and autism spectrum disorder in children born to mothers with thyroid dysfunction: a Danish nationwide cohort study

OBJECTIVE

To examine the association between maternal hyper- and hypothyroidism and the risk of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in the child.

DESIGN

A population-based cohort study.

SETTING

Singletons liveborn in Denmark between 1991 and 2004.

POPULATION

A total of 857 014 singletons alive and living in Denmark at the age of 3 years.

METHODS

Information on the diagnosis and/or treatment of maternal thyroid disease and the neurodevelopmental disorders ADHD and ASD in the child was obtained from Danish nationwide registers. The Cox proportional hazards model was used to estimate the hazard ratio (HR) with 95% confidence interval (95% CI) for risk of ADHD and ASD in children born to mothers with thyroid dysfunction, adjusting for potential confounding factors.

MAIN OUTCOME MEASURES

ADHD and ASD in the child.

RESULTS

Altogether, 30,295 singletons (3.5%) were born to mothers with thyroid dysfunction. Maternal hyperthyroidism diagnosed and treated for the first time after the birth of the child increased the risk of ADHD in the child (adjusted HR 1.23; 95% CI 1.05-1.44), whereas hypothyroidism increased the risk of ASD (adjusted HR 1.34; 95% CI 1.14-1.59). No significant association was seen for maternal diagnosis and treatment prior to the birth of the child.

CONCLUSIONS

Children born to mothers diagnosed and treated for the first time for thyroid dysfunction after their birth may have been exposed to abnormal levels of maternal thyroid hormone already present during the pregnancy, and this untreated condition could increase the risk of specific neurodevelopmental disorders in the child.

Hypothyroidism in pregnancy

Hypothyroidism is the most common pregnancy-related thyroid disorder, affecting 3-5% of all pregnant women. Subclinical hypothyroidism is more common than is overt hypothyroidism, and is usually defined as a serum thyroid-stimulating hormone (TSH) concentration greater than the pregnancy-specific reference range for each laboratory value, or by serum TSH concentrations greater than 2·5 mIU/L in the first trimester and greater than 3 mIU/L in the second and third trimesters. Some authors have defined subclinical hypothyroidism as a serum TSH between 5 and 10 mIU/L, and overt hypothyroidism as a serum TSH greater than 10 mIU/L, but this is not the commonly accepted definition. Once overt hypothyroidism is diagnosed, treatment with levothyroxine should be started to achieve serum TSH concentrations within the reference ranges for pregnancy as soon as possible. For patients with subclinical hypothyroidism, recommendations for therapy differ between various professional groups as a result of inconsistent data from both observational studies and clinical trials regarding the benefits for the mother or the child. Similarly, because benefits of therapy are still uncertain, universal screening of all pregnant women for subclinical hypothyroidism or thyroid autoimmunity is not recommended by most professional groups. During gestation, an increase in levothyroxine dose is required in more than 50% of women with previously diagnosed hypothyroidism, and can be managed by increasing the levothyroxine dose by 30% when pregnancy is confirmed.