Thyroid stimulating hormone (TSH) ≥2.5mU/l in early pregnancy: Prevalence and subsequent outcomes

Effect of levothyroxine treatment on fetal growth among women with mild subclinical hypothyroidism and thyroid peroxidase antibody negative: a cohort study

BACKGROUND

Some clinicians used levothyroxine (LT4) treatment for mild subclinical hypothyroidism (SCH) pregnant women (2.5 < thyroid-stimulating hormone (TSH) ≤ the pregnancy-specific reference range with normal free thyroxine (FT4) level) with thyroid peroxidase antibody negative (TPOAb^-), although the recent clinical guideline did not recommend it. It is unknown whether LT4 treatment for pregnant women with mild SCH and TPOAb^- have impact on fetal growth. Therefore, the aim of the study was to investigate the effect of LT4 treatment on fetal growth and birth weight among mild SCH pregnant women with TPOAb^-.

METHODS

This was a birth cohort study including 14,609 pregnant women between 2016 and 2019 in Tongzhou Maternal and Child Health Hospital of Beijing, China. Pregnant women were divided into 3 groups as follows: Euthyroid (n = 14,285, 0.03 ≤ TSH ≤ 2.5mIU/L, normal FT4), TPOAb^-; Untreated mild SCH with TPOAb^- (n = 248, 2.5 < TSH ≤ 2.9mIU/L, normal FT4, without LT4 treatment); Treated mild SCH with TPOAb^- (n = 76, 2.5 < TSH ≤ 2.9mIU/L, normal FT4, with LT4 treatment). The main outcome measures were Z-scores of fetal growth indicators (abdominal circumference (AC), biparietal diameter (BPD), femur length (FL), head circumference (HC), estimated fetal weight (EFW)), fetal growth restriction (FGR) and birth weight.

RESULTS

There was no difference in fetal growth indicators and birth weight between the untreated mild SCH women with TPOAb^- and the euthyroid pregnant women. But the HC Z-score was lower in the LT4 treated mild SCH women with TPOAb^-, compared with the euthyroid pregnant women (β = -0.223, 95%CI: -0.422, -0.023). The LT4 treated mild SCH women with TPOAb^- had lower fetal HC Z-score (β = -0.236, 95%CI: -0.457, -0.015), compared with the untreated mild SCH women with TPOAb^-.

CONCLUSIONS

We observed that LT4 treatment for mild SCH with TPOAb^- was associated with decreased fetal HC, which was not observed for untreated mild SCH women with TPOAb^-. The adverse effect of LT4 treatment for mild SCH with TPOAb^- provided new evidence for the recent clinical guideline.

Pregnancy outcomes and newborn characteristics in women with follicular fluid thyroid autoantibodies undergoing assisted reproduction

Background

Higher levels of thyroid autoantibodies in follicular fluid (FF) of thyroid autoimmunity (TAI) positive women are strongly correlated with serum levels and may have effect on the post-implantation embryo development. Literature highlights that levothyroxine (LT4) treatment may attenuate the risk of adverse pregnancy outcomes. The aim of the study was to estimate the pregnancy and newborn outcomes in women with FF thyroid autoantibodies undergoing assisted reproductive technology (ART).

Methods

The study population included 24 women with confirmed clinical pregnancy, 8 TAI positive and 16 TAI negative women. LT4 supplementation was applied in 20.8% patients, TAI positive.

Results

Pregnancy outcomes were: twin pregnancy rate 41.7%, early miscarriage rate 8.3%, late miscarriage rate 4.2%, preterm birth rate 16.7%, term birth rate 70.8%, live birth rate 96.0%. There was significant difference in serum and in FF TgAbs (p< 0.001)between the groups according to TAI, while serum fT₃ was lower in the group with TAI (p = 0.047). Serum P₄ was higher in LT4 treated group (p = 0.005), with TAI, and newborns in this group had higher birth weight (p = 0.001) and height (p = 0.008). Maternal complications occurred in 23.8% of patients. No congenital malformations in newborns were noted.

Conclusions

Thyroid autoantibodies present in FF may have an effect on the post-implantation embryo development, but have no effect on further course of pregnancy. The special benefit of LT4 treatment for successful ART outcome was demonstrated for newborn anthropometric parameters.

A Bayesian model to estimate the cutoff value of TSH for management of preterm birth

BACKGROUND

Determining a thyroid hormone cutoff value in pregnancy is challenging issue and several approaches have been introduced to optimize a utility function. We aimed to estimate the cutoff value of TSH using Bayesian method for prediction of preterm-birth.

METHODS

This study was a secondary-analysis of the population-based data collected prospectively within the framework of the Tehran Thyroid and Pregnancy Study. A total of 1,538 pregnant women attending prenatal clinics.

RESULTS

Using Bayesian method resulted a TSH-cutoff of (3.97mIU/L,95%CI:3.95-4.00) for distinguishing pregnant women at risk of preterm-birth. The cutoff was associated with acceptable positive predictive and negative predictive values (0.84,95% CI:0.80-0.88) and 0.92 (95%CI: 0.91-0.94), respectively). In women who were negative for thyroid peroxides antibody (TPOAb) with sufficient urinary iodine concentration (UIC), the TSH cutoff of 3.92 mIU/L(95%CI:3.70-4) had the highest predictive value; whereas in TPOAb positive women with insufficient UIC, the cutoff of 4.0 mIU/L(95%:CI 3.94-4) could better predict preterm birth. Cutoffs estimated in this study are close to the revised TSH value of 4.0mIU/L which is currently recommended by the American Thyroid Association.

CONCLUSION

Regardless of TPOAb status or iodine insufficiency, risk of preterm labor is increased in pregnant women with TSH value of > 3.92 mIU/L; these women may benefit from Levothyroxine (LT4) therapy for preventing preterm birth.

Subclinical hypothyroidism in women's health: from pre- to post-menopause

OBJECTIVE

Subclinical hypothyroidism (SCH) is a quite frequent condition among women, affecting 3-12% of the general population. Its consequences on women's health in reproductive age, pregnancy and menopause have been extensively investigated but data about the effective impact of treatment with levothyroxine (LT4) remain conflicting.

METHODS

This is a narrative review and analysis of the most relevant data until June 2021.

RESULTS

SCH may affect reproduction. Evidence suggests that women with SCH undergoing assisted reproductive technique (ART) may benefit from LT4 therapy whereas there are no conclusive data regarding women attempting natural conception. SCH may be associated with several negative pregnancy outcomes, that is to say recurrent pregnancy loss (RPL), preterm delivery, preeclampsia and neurocognitive disturbances of offspring. However, the protective role of LT4 treatment has been established in selected cases, for instance in thyroid peroxidase antibody (TPOAb) -positive women with TSH greater than the pregnancy specific reference range and/or in TPOAb-negative women with TSH >10.0 mIU/L. In menopause, SCH can worsen the negative cardio-metabolic effects of hormonal loss and/or aging, by exacerbating dyslipidaemia and hypertension. Nevertheless, robust data about the benefits of LT4 therapy are still lacking and treatment should be encouraged with caution.

CONCLUSIONS

SCH represents a challenging condition during pre- and post- menopause. An aware knowledge of its possible principal consequences could help all clinicians who are involved in women's health to manage more properly it, preventing its sequelae.

Subclinical Hypothyroidism with Negative for Thyroid Peroxidase Antibodies in Pregnancy: Intellectual Development of Offspring

Background: The adverse impact of maternal negative TPOAb of gestational subclinical hypothyroidism (SCH-TPOAb^-) on the development of the offspring has not yet been clearly identified. A lingering controversy exists over the treatment of SCH-TPOAb^- diagnosed during pregnancy. Therefore, this study was designed to evaluate the intellectual development of children of mothers who had SCH-TPOAb^-. Methods: A number of 139 children were recruited; 112 children were born to SCH TPOAb^- and 27 children were born to euthyroid TPOAb^- mothers. Based on the mothers' thyrotropin (TSH) levels during pregnancy and whether or not they received levothyroxine (LT4) treatment, the children were assigned to four groups: Group A (2.5 mIU/L < TSH ≤4.0 mIU/L, n = 31) and Group B (4.0 mIU/L < TSH ≤10.0 mIU/L, n = 26), whose mothers were treated with LT4 before eight gestational weeks, and Group C (2.5 mIU/L < TSH ≤4.0 mIU/L, n = 27) and Group D (4.0 mIU/L < TSH ≤10.0 mIU/L, n = 28), whose mothers received no treatment. A total number of 27 children whose mother's serum TSH was <2.5 mIU/L and were TPOAb^- during their pregnancy served as the control group (Group E). The intellectual development of two-year-old children was assessed and compared using the Gesell Development Diagnosis Scale. Results: The developmental quotient (DQ) in Group D was 8.67 lower than this in Group E (p < 0.001). More specifically, gross motor quotient, fine motor quotient, adaptability quotient (ABQ), language quotient (LQ), and individual social behavior quotient (ISBQ) of DQ in Group D were significantly lower than those in Group E. No significant differences were observed in DQ among Group A, Group B, Group C, and Group E (p > 0.05). Spearman's rank correlation analysis showed that DQ, FMQ, ABQ, LQ, and ISBQ were significantly negatively correlated with the TSH level (r = -0.417, -0.253, -0.273, -0.436, and -0.272; p < 0.05). In addition, multivariate logistic regression analysis revealed that mothers' education (short education), mothers' education (medium education), and TSH level (4.0 mIU/L < TSH ≤10.0 mIU/L) were both risk factors affecting the intellectual development of the offspring (p < 0.05). Conclusion: The effects of the intellectual development of the offspring with SCH-TPOAb^- are related to the level of TSH. Standardized treatment for SCH-TPOAb^- pregnant women before eight gestational weeks, whose TSH level was from 4.0 to 10.0 mIU/L, may significantly improve the intellectual development levels of the approximately two-year-old offspring. Although our study was a historical cohort study, the data analyzed provide the foundation for further investigation. Further prospective intervention trials with large numbers of participants are needed to confirm our conclusions. The Clinical Trial Registration number is 2021-K-84-02.

Impact of Early Pregnancy Subclinical Hypothyroidism on Gestational Diabetes Mellitus: A Retrospective Study of 7,536 Cases

Background: Maternal subclinical hypothyroidism (SCH) has been associated with adverse pregnancy outcomes. This study aimed to explore whether SCH in the first trimester contributed to the development of gestational diabetes mellitus (GDM). Materials and Methods: A total of 8,777 pregnant women who first visited before 13 weeks and 6 days of gestation and accepted routine prenatal service at the Third Affiliated Hospital of Sun Yat-Sen University from January 2015 to September 2018 were recruited in this study. Thyroid functions (thyroid stimulating hormone [TSH], free T4, and thyroid peroxidase antibody [TPOAb]) were measured before 13 weeks and 6 days of gestation and data of 7,536 subjects with TSH ≥0.1 mIU/L were analyzed. A 2-hour 75-g oral glucose tolerance test was performed between 24 and 28 gestational weeks. Chi-square test and multivariate logistic regression analysis were applied to evaluate the relationship between SCH and GDM. Results: The prevalence of SCH in this population was 7.53%. After stratifying the relationship between SCH and GDM according to TSH concentrations (slightly elevated TSH: ≥2.5, <4.0 mIU/L; moderately elevated TSH: ≥4.0, <10.0 mIU/L) and TPOAb status, a moderately elevated TSH combined with positive TPOAb (23.9% vs. normal 13.0%, chi-square = 6.317, p = 0.012) was found to increase the incidence of GDM. Furthermore, after adjusting for confounders (maternal age, educational levels, parity, and pregestational body mass index [preBMI]), the SCH group still exhibited a higher risk of GDM (relative risk [RR] 1.867, 95% confidence interval [CI] 1.018-3.424). Conclusion: Our findings indicated that SCH during early pregnancy, in the presence of moderately elevated TSH levels and positive TPOAb, might lead to an increased risk of GDM.

Subclinical thyroid dysfunction in the first trimester of pregnancy: 'Disease' versus physiological (pulsatile) variation in TSH concentrations

BACKGROUND

There is no universal consensus regarding cut-off points for TSH in pregnancy, so concentrations of 2.5 or 4.0 mIU/L were suggested for first trimester (Endocrine Society [2012] and ATA [2017] guidelines, respectively). Yet, the impact of physiological variation in TSH secretion has not been assessed.

SUBJECTS AND METHODS

We assessed baseline concentrations of free T4, free T3 and TSH at 30-minute intervals (between 7.00 and 9.00 hours) in 110 healthy pregnant women, age 30.2 ± 6.0 years, 9.9 ± 2.4 weeks of gestation, and in 19 female controls, age 28.9 ± 10.7.

RESULTS

Mean TSH concentrations in pregnant women were 1.62 ± 1.26 mIU/L and on average varied by 39.5% (dispersion between the highest and the lowest TSH), with no difference in TSH variation between pregnant women and controls. Taking into account the highest TSH out of five consecutive measurements, TSH >2.5 mIU/L and TSH above 4.0 mIU/L were found in 23 (20.9%) and 10 (9.1%) pregnant women, respectively. In contrast, when the lowest TSH value was considered, then concentrations of TSH >2.5 mIU/L and >4.0 mIU/L were found in 14 (12.7%) and 4 (3.6%) women, respectively. This discrepancy was even more pronounced in aTPO-negative subjects (21 [21.2%] vs 8 [8.1%] women, for TSH >2.5 mIU/L, and six [6.06%] vs one [1.01%], for TSH >4.0 mIU/L). Furthermore, either six (5.4%) or 10 (9.1%) women had TSH concentrations below 0.1 mIU/L.

CONCLUSIONS

In a significant number of patients, diagnosis of subclinical thyroid dysfunction could be erroneously made not as a result of 'disease', but as a result of physiological variation in TSH concentrations.

Subclinical hypothyroidism is not associated with neonatal morbidity in women with gestational diabetes mellitus: a case-control study

PURPOSE

Placental modifications observed in women with subclinical hypothyroidism (SCH) should be associated with altered fetal development in women with gestational diabetes mellitus (GDM) and worsen perinatal outcome. We aim to determine if SCH is associated with neonatal morbidity in women with GDM.

METHODS

A secondary analysis of data collected for a prospective population-based cohort study including all pregnant women with singleton pregnancies at diagnosis of GDM in a tertiary care university hospital. Thyroid-stimulating hormone and free thyroxine were measured at diagnosis of GDM. Perinatal outcome was compared between two groups-women with SCH and euthyroid. Neonatal morbidity was defined by at least one of the following criteria: preterm birth, macrosomia, shoulder dystocia, respiratory distress syndrome, 5-min Apgar score < 7, pH < 7.10, and admission to the NICU (neonatal intensive-care unit) for 24 h.

RESULTS

Of the total 200 women enrolled, 150 were evaluable for the study. Of whom, 9 (6%) women presented SCH. The mean gestational age at diagnosis of GDM was 21.7 ± 7.0 weeks. Maternal outcome of women with SCH was similar to euthyroid women. Neonatal morbidity occurred in 17.3% (26/150). Women with SCH had higher rate of neonatal morbidity (44.4% vs. 15.6%; p = 0.03), specifically due to admission to the NICU for 24 h (33.3% vs. 5.7%; p = 0.02). SCH in women with GDM is not associated with neonatal morbidity after controlling for gestational age at birth and admission to NICU (adjusted OR 2.02, 95% CI 0.75-10.23).

CONCLUSION

Subclinical hypothyroidism is not associated with neonatal morbidity in women with gestational diabetes mellitus.

Thyroid disorders in subfertility and early pregnancy

Disorders of thyroid function are common in pregnancy and have implications for foetal and maternal health. Thyroid autoimmunity, as evidenced by the presence of elevated levels of anti-thyroid antibodies (anti-TPO and anti-Tg antibodies) is associated with an increased risk of miscarriage, though the mechanism remains poorly understood. There has been considerable focus on the implications and optimal management of pregnant women with thyroid disease, especially those undergoing assisted reproduction. Pregnancy results in significant changes in thyroid physiology and these need to be understood by clinicians involved in the care of pregnant women. Guidelines for the use of thyroxine and target thyroid function tests have been produced by international bodies but it is recognised that these predominantly reflect expert opinion rather than established evidence-based practice. Importantly a number of key clinical trials have been performed to aid understanding, particularly of the consequences of hypothyroidism for mother and baby, and the effectiveness of thyroid hormone use in autoimmune and subclinical hypothyroidism. This review summarises the current knowledge base and guidance for practice relating to thyroid disorders in pregnancy and subfertility.

Effects of Maternal Subclinical Hypothyroidism in Early Pregnancy Diagnosed by Different Criteria on Adverse Perinatal Outcomes in Chinese Women With Negative TPOAb

Aims: To compare the effects of maternal subclinical hypothyroidism (SCH) diagnosed by the 2011 or 2017 "Guidelines of the American Thyroid Association (ATA) for the diagnosis and management of thyroid disease during pregnancy and the postpartum" during the first trimester on adverse pregnancy outcomes in thyroid peroxidase antibody (TPOAb)-negative pregnant women. Methods: There were 1,556 Chinese singleton pregnant women with negative TPOAb diagnosed with either SCH or euthyroidism who were investigated, and the prevalence and risk of obstetric outcomes were compared between the two groups using 2011 and 2017 ATA standards, respectively. The effects of a mildly elevated thyroid-stimulating hormone (TSH) concentration on adverse pregnancy outcomes were evaluated by binary logistic regression. Results: Maternal SCH identified by the 2011 ATA guidelines correlated with higher rates and risks of pregnancy-induced hypertension (PIH), preeclampsia, and low-birth-weight infants, while maternal SCH diagnosed by the 2017 ATA guidelines was more likely to develop PIH, preeclampsia, cesarean delivery, preterm delivery, placenta previa, and total adverse maternal and neonatal outcomes. Moreover, a mildly elevated TSH level was significantly associated with PIH after adjustment for confounding factors. Conclusions: Compared with the 2011 ATA guidelines, the 2017 ATA guidelines could be more applicable to Chinese pregnant women to screen the effects of SCH on the majority of adverse pregnancy outcomes.

The Need for Dynamic Clinical Guidelines: A Systematic Review of New Research Published After Release of the 2017 ATA Guidelines on Thyroid Disease During Pregnancy and the Postpartum

Background: The American Thyroid Association Guidelines on Thyroid Disease During Pregnancy and the Postpartum (ATA Guidelines) were published in 2017, with an update not expected for another 5 years. Since release of the 2017 ATA Guidelines, greater than 500 articles have been published in the field. Furthermore, there are presently 14 prospective, interventional trials in progress registered at Clinicaltrials.gov Static guidelines updated every 5-7 years fail to provide timely evidence-based guidance to practicing clinicians. Consequently, guideline development should move toward the creation of dynamic documents. The present article reviews the literature published since the 2017 ATA Guidelines, both to benefit clinicians in practice and to make the case for Dynamic ATA Guidelines. Methods: Using the search terms "thyroid" and "pregnancy," a systematic review of literature published in Pubmed from 3/1/2017 to 12/31/2018 was conducted. The titles and/or abstracts of all articles were reviewed. All articles were classified by subject headings used in the 2017 ATA Guidelines. English-text articles classified under "hypothyroidism" or "thyroid autoimmunity" were examined in full-text. Using the questions and recommendations put forth by the previous ATA Guidelines, relevant articles were selected for discussion in this review. Results: At the time of the search, 659 unique articles on "thyroid and pregnancy" were identified, including 66 original studies on hypothyroidism and 26 on thyroid autoimmunity. Of these, 26 studies on hypothyroidism and 18 studies on thyroid autoimmunity were selected for inclusion in this review based on specific questions in the 2017 ATA Guidelines. Based on these 44 articles, we propose two specific changes to the 2017 ATA Guidelines. Conclusion: Based on new research, we recommend the 2017 ATA Guidelines be updated to recommend against treating thyroid antibody-negative women diagnosed with subclinical hypothyroidism in the second trimester or later; to reflect new, moderate-quality evidence supporting the treatment of thyroid peroxidase antibody-negative women with elevated thyroid stimulating hormone levels in the first trimester or earlier; and to recommend against treatment of euthyroid, thyroid peroxidase antibody-positive women undergoing assisted reproductive technology. Transitioning to a Dynamic ATA Guidelines would allow for these and future recommendations to be implemented in real time.

Differences in Diagnostic Criteria Mask the True Prevalence of Thyroid Disease in Pregnancy: A Systematic Review and Meta-Analysis

BACKGROUND

The reported prevalence of thyroid disease in pregnancy varies widely through the published literature. These discrepancies are due to differences in criteria for euthyroidism, nationality, iodine status, and gestational age at screening. As a result, currently, an accepted rate of prevalence does not exist for the various thyroid diseases in pregnancy. Understanding the true prevalence rates of these disorders has important implications for clinical management and the ongoing discussion regarding universal screening. The aims of this study were to assess (i) the true prevalence of thyroid disorders in pregnancy and (ii) the impact of diagnostic methodology on these rates.

METHODS

A systematic review was conducted of the existing literature, including the Pubmed database and references from relevant review articles. Sixty-three studies reporting prevalence of overt hypothyroidism, subclinical hypothyroidism, isolated hypothyroxinemia, subclinical hyperthyroidism, and overt hyperthyroidism in pregnant women were included. Studies were further classified by thyrotropin (TSH) cutoff for diagnosis in hypothyroid disease and timing of screening for hyperthyroid disease. Meta-analysis yielded pooled prevalence rates, with subgroup analyses for TSH cutoff and timing of screening. Analysis of studies using the 97.5th percentile TSH cutoff was assessed to yield the most accurate prevalence rates for hypothyroidism.

RESULTS

Pooled prevalence rates for hypothyroidism calculated from studies using the 97.5th percentile as an upper limit for TSH were 0.50% for overt hypothyroidism, 3.47% for subclinical hypothyroidism, and 2.05% for isolated hypothyroxinemia. Pooled prevalence rates in the first and second trimesters for hyperthyroidism were 0.91% and 0.65%, respectively, for overt hyperthyroidism and 2.18% and 0.98%, respectively, for subclinical hyperthyroidism.

CONCLUSION

Population-based, trimester-specific TSH cutoffs for diagnosis of hypothyroid disease in pregnancy result in more accurate diagnosis and better estimates for prevalence of disease. Prevalence of hyperthyroidism in pregnancy varies depending on timing of screening. The prevalence rates reported in this study represent the best estimate to date of the true rates of thyroid disease in pregnancy.

The prevalence of maternal hypothyroidism in first trimester screening from 11 to 14 weeks of gestation

AIM

The aim of this study was to determine the prevalence of maternal hypothyroidism in the first trimester from 11 to 14 weeks of gestation according to the American Thyroid Association (ATA) guidelines from 2017 and to compare the rates for singleton and twin pregnancies.

METHODS

A total of 4965 consecutive Caucasian singleton pregnancies and 109 Caucasian twin pregnancies were included in the investigation. Patients with a history of thyroid gland disorder were excluded. Subclinical maternal hypothyroidism was defined as a thyroid stimulating hormone (TSH) concentration above the 97.5^th percentile and free thyroxine (fT4) within the range of a reference population of women at 11-14 weeks of gestation. Overt maternal hypothyroidism was defined as a TSH concentration above the 97.5^th percentile and an fT4 below the 2.5^th percentile of the reference population.TSH, fT4, and anti thyroid peroxidase antibody (TPOAb) were measured by immunochemiluminescent assays on an 16200 Abbott Architect analyzer.

RESULTS

The prevalence of hypothyroidism for twin pregnancies was no higher than that for singleton pregnancies; 6.42% (7/109) vs. 5.32% (264/4965), respectively; P=0.61. All twin pregnancies were subclinical. Singleton hypothyroid pregnancies included 4.91% (244 cases) of subclinical and 0.41% (20 cases) of overt hypothyroidism. The prevalence of TPOAb positive hypothyroid women for twin pregnancies and singleton pregnancies was 71% (5/7) vs. 52% (137/264 cases), respectively but the differences were not statistically significant; P=0.31.

CONCLUSION

Each first trimester screening center should establish its TSH and fT4 reference ranges. Our center had higher upper reference limits of TSH than that of the universally fixed limit of 2.5 mU/L, which led to a lower measured prevalence of maternal hypothyroidism. A large number of hypothyroid women were TPOAb positive.

Effect of mildly elevated thyroid-stimulating hormone during the first trimester on adverse pregnancy outcomes

BACKGROUND

To investigate the effect of a mildly elevated thyroid-stimulating hormone (TSH) concentration between 2.5 and 4.0 mIU/L during the first trimester on pregnancy outcomes in thyroid peroxydase antibody (TPOAb)-negative pregnant women.

METHODS

A total of 1858 pregnant women who were TPOAb-negative before 13^+ 6 gestational weeks, received regular prenatal services, and delivered in the third affiliated hospital of Sun Yat-Sen University were recruited from June 2016 to June 2017. Measurements of thyroid function (TSH, free T4 [FT4] and TPOAb) and adverse pregnancy outcomes were assessed and recorded.

RESULTS

Among the 1858 study participants, the 97.5th percentile for TSH was 3.76 mIU/L, and 142 women (7.6%) had mildly elevated TSH levels between 2.5 and 4.0 mIU/L. No differences in the incidence of adverse pregnancy outcomes were observed between patients with a mildly elevated TSH level and those with a normal TSH level (< 2.5 mIU/L).

CONCLUSION

A mildly elevated TSH concentration (2.5-4.0 mIU/L) during the first trimester of pregnancy in TPOAb-negative women was not associated with adverse pregnancy outcomes in our study population. Accordingly, it may be possible to raise the upper limit of the healthy TSH reference range for pregnant women.

Validation of Billewicz Scoring System for Detection of Overt Hypothyroidism During Pregnancy

BACKGROUND

Currently, various clinical and laboratory diagnostic methods are used to detect overt hypothyroidism during pregnancy. The Billewicz scoring index, as a clinical scale for detection of hypothyroidism, has been applied in general populations; however, its application during pregnancy remains a controversial subject of ongoing research.

OBJECTIVES

The purpose of this study was to evaluate the diagnostic value of Billewicz scoring index for overt hypothyroidism in a general population of Iranian pregnant women.

METHODS

This study was conducted on 1843 pregnant women. A comprehensive questionnaire, including Billewicz scoring items, was completed, and relevant clinical examinations were performed. The participants underwent serum measurements of thyroxine (T4), thyroid hormone uptake, thyroid-stimulating hormone (TSH), and thyroid peroxidase antibody (TPOAb). Using the receiver operating characteristic (ROC) curve analysis, the optimal sensitivity and specificity were determined as values with maximum yields on the Youden and Rsquo's Index (sensitivity + specificity-1).

RESULTS

The prevalence of overt hypothyroidism and subclinical hypothyroidism was 3.3% and 28.6%, respectively. Overall, 3.6%, 18.9%, and 50% of euthyroid, subclinical hypothyroid, and overt hypothyroid women were TPOAb-positive, respectively. The mean Billewicz scores of euthyroid, overt hypothyroid, and subclinical hypothyroid women were -41.16 (11.16), -17.11 (13.63), and -40.1 (11.2), respectively. Based on the Billewicz scale, at least one sign of hypothyroidism was reported in 38.84% (n, 491) of euthyroid women. Scores ≤ -26.5 (sensitivity, 100%; specificity, 90.82%) were considered as the optimal scores for predicting overt hypothyroidism (Ldquo, Norisk, and Rsquo).

CONCLUSIONS

The Billewicz clinical scoring system, as a reliable and inexpensive clinical tool, used along with laboratory measurements, can help screen overt hypothyroidism during pregnancy, primarily in low-resource settings.

Impact of TSH during the first trimester of pregnancy on obstetric and foetal complications: Usefulness of 2.5 mIU/L cut-off value

OBJECTIVE

An association of pregnancy outcomes with subclinical hypothyroidism has been reported; however, there still exists a strong controversy regarding whether subclinical hypothyroidism ought to be dealt with or not. The objective of the study was to evaluate the association of foetal-maternal complications with first trimester maternal Thyrotropin (TSH) values.

DESIGN

A retrospective study in a single tertiary care hospital was performed.

PATIENTS

A total of 1981 pregnant women were studied during 2012.

MEASUREMENTS

Thyrotropin (TSH) universal screening was performed between 9 and 12 weeks of gestation. Outcomes included foetal-maternal complications and newborn health parameters.

RESULTS

Median TSH was 1.72 (0.99-2.61) mIU/L. The incidence of perinatal loss, miscarriage and stillbirth was 7.2%, 5.9% and 1.1%, respectively. Median TSH of women with and without miscarriage was 1.97 (1.29-3.28) vs 1.71 (0.96-2.58) mIU/L (P = .009). Incidence of pre-eclampsia was 3.2%; TSH in these women was 2.10 (1.40-2.74) vs 1.71 (0.98-2.59) mIU/L in those without (P = .027). TSH in women with dystocia in labour was 1.76 (1.00-2.53) vs 1.68 (0.94-2.59) mIU/L in those who gave birth with normal progression (P = .044). Women with TSH 2.5-5.1 mIU/L had a higher risk of perinatal loss [OR 1.589 (1.085-2.329)], miscarriage [OR 1.702 (1.126-2.572)] and premature birth [OR 1.39 (1.013-1.876)], adjusted by mother's age. There was no association with the other outcomes analysed.

CONCLUSIONS

There is a positive association between maternal TSH in the first trimester of pregnancy and the incidence of perinatal loss and miscarriage. The TSH cut-off value of 2.5 mIU/L identified women with higher adverse pregnancy outcomes.