Postpartum Thyroid Dysfunction Research Articles

Immunological and ultrasound characteristics of different forms of postpartum thyroid dysfunction

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Pregnancy-Related Thyroid Dysfunction And Its Effects A Single-Center Study

This research aimed to evaluate the consequences of pregnancy-related thyroid dysfunction on 100 participants. All patients had their thyroid stimulating hormone (TSH), free thyroxine (FT3), and free triiodothyronine (FT4) measured before, during, and after pregnancy. Thyroid hormones and neck ultrasounds were also performed. According to the research, 86.0% of pregnant women had abnormal TSH levels. Of them, 28% had TSH levels over 4.2mIU/L, and 10% had values in the 2.5–4.2mIU/L range. Most patients' FT3 and FT4 levels were within the normal range during pregnancy. Most patients (59%) had postpartum thyroid dysfunction; ultrasonography demonstrated goitre in 56% of patients and cystic lesions in 8%. TSH concentrations between 2.5 and 4.2 mIU/L and higher than 4.2 mIU/L were found in 14% and 36% of individuals, respectively. According to the study's findings, pregnancy-related thyroid dysfunction is a prevalent illness in the population under investigation. It may dramatically impact both the mother's and the baby's health.

Vitamin D categories and postpartum thyroid function in women with hypothyroidism.

ObjectiveTo analyze the related factors of the postpartum thyroid function in women with overt hypothyroidism (OH)/subclinical hypothyroidism (SCH) and explore the effects of vitamin D categories.MethodsThyroid hormones, thyroid autoantibody, and serum 25OHD levels were continuously recorded from the first trimester of pregnancy (T1) to the 12th postpartum month. Logistic regression analysis and Cox regression analysis were used to screen the related factors of postpartum thyroid function, and the Latent Class Growth Model was performed to analyze the trajectory characteristics of serum 25OHD levels.ResultsTotally, 252 pregnant women with OH/SCH were enrolled in the study. In the 12th month postpartum, 36.5% of the patients improved thyroid function, 37.3% continued hypothyroidism, and 26.2% developed thyroid dysfunction. Vitamin D sufficiency, positive TPOAb, and positive TgAb in T1 were independent prognostic factors of postpartum thyroid function. Vitamin D sufficiency in T1 was illustrated as an independent factor of the improved postpartum thyroid function, but the protective effect for the developed postpartum thyroid dysfunction was only confirmed in TPOAb-positive patients. Cox regression analysis further confirmed the effects of vitamin D categories. Notably, the high-level 25OHD trajectory during pregnancy and postpartum could predict improved postpartum thyroid function and decrease the risk of developed postpartum thyroid dysfunction.ConclusionAppropriate vitamin D nutrition during pregnancy and postpartum may be beneficial to postpartum thyroid function.

An update on thyroid disorders in the postpartum period.

To review the pathophysiology, diagnosis and management of postpartum thyroid dysfunction, and related management of thyroid disorders during lactation. We reviewed the literature on postpartum thyroid dysfunction and management of thyroid disorders during lactation. The postpartum period is characterized by a rebound from the immunotolerance induced by pregnancy. Routine thyroid function screening is not recommended for asymptomatic women in the postpartum period. Testing thyroid function should be considered at 6-12-week postpartum for high-risk populations, including women with a previous episode of postpartum thyroiditis, Graves' disease, or those with Hashimoto's thyroiditis on thyroid hormone replacement, known thyroid peroxidase antibody positivity, type 1 diabetes mellitus, other nonthyroidal autoimmune disease, or chronic hepatitis C. A serum TSH should also be checked in the setting of postpartum depression or difficulty lactating. If patients have thyrotoxicosis, new-onset or recurrent Graves' disease must be differentiated from postpartum thyroiditis, because the management differs. Periodic thyroid function testing is recommended following recovery from postpartum thyroiditis due to high lifetime risk of developing permanent hypothyroidism. Levothyroxine, and the lowest effective dose of antithyroid drugs, (propylthiouracil, methimazole, and carbimazole) can be safely used in lactating women. The use of radiopharmaceutical scanning is avoided during lactation and radioactive iodine treatment is contraindicated. Diagnosing postpartum thyroid dysfunction is challenging, because symptoms may be subtle. A team approach involving primary care providers, endocrinologists, and obstetricians is essential for transitioning thyroid care from the gestational to the postpartum setting.

Postpartum Thyroid Dysfunction in Women With Known and Newly Diagnosed Hypothyroidism in Early Pregnancy.

BackgroundHypothyroidism in the first trimester of pregnancy (T1) has great adverse effects on mothers and foetuses. However, few studies have investigated the influence on postpartum thyroid dysfunction. This study aimed to evaluate their long-term effect on postpartum thyroid function within one year after delivery.MethodsIn total, 151 women were recruited from 1496 participants and were classified as newly diagnosed subclinical hypothyroidism (SCH) in T1 (ND-SCH, n=50), previously known SCH before pregnancy (PK-SCH, n=51) and previously known overt hypothyroidism (PK-OH, n=50). Their thyroid functions were dynamically monitored from pre-conception to one-year postpartum.ResultsDuring pregnancy, the first thyroid functions’ test time in T1 were 5-8 gestational weeks. After delivery, the prevalence of postpartum thyroiditis (PPT) was comparable in women with previously known and newly diagnosed hypothyroidism [ND-SCH 62.0% vs PK-SCH 64.7% vs PK-OH 64.0%, P=0.96]. For the ND-SCH group, PPT was significantly related with thyroid-stimulating hormone (TSH) >4.0 mU/L occurring at <8 gestational weeks [OR=8.06, 95% CI, 2.08-31.29] and TSH levels outside 1.0-2.5 mU/L near childbirth [OR=3.73, 95% CI, 1.04-13.41]. For patients with known hypothyroidism before pregnancy (PK-SCH and PK-OH), TSH>2.5 mU/L in T1 [OR=3.55, 95% CI, 1.43-8.81] and TPOAb≥300 μIU/mL [OR=6.58, 95% CI, 2.05-21.12] were associated with PPT. Regardless of whether SCH was diagnosed before pregnancy or in T1, the levothyroxine (LT4) treatment was discontinued at delivery. More than 50% of the patients had to face the hypothyroidism phase of postpartum and restarted LT4 treatment in the first-year follow-up. The logistic regression analysis revealed that TSH elevation occurring at <8 gestational weeks [OR=2.48, 95% CI, 1.09-5.6], TSH levels outside 1.0-2.5 mU/L near childbirth [OR=3.42, 95% CI, 1.45-8.05], and TPOAb≥300 μIU/mL [OR=6.59, 95% CI, 1.79-24.30] were the risk factors.ConclusionTSH elevation at <8 gestational weeks was associated with PPT after delivery in women with known and newly diagnosed hypothyroidism. Especially for SCH patients who stopped LT4 treatment at delivery, unsatisfactory TSH level at <8 gestational weeks and near childbirth, TPOAb≥300 μIU/mL were the risk factors for LT4 retreatment in one-year postpartum.

High Prevalence of Anti Thyroid Antibodies in an Albanian Cohort of Patients

Introduction: Albania is classified as iodine deficient region and endemic goiter in this country has been a concern for public health. A salt iodization program has been implemented in Albania since 2008. Most of regions still remain with a mild or moderate iodine deficiency there are no studies on prevalence of thyroid autoimmune disorders. The purpose of this study was to assess thyroid function and the presence of thyroid antibodies in subjects that were not previously diagnosed or treated for thyroid disorders. Methods: This is a cross-sectional study performed in a cohort of patients in Albania during a 2 year period (january 2018-january 2020). We assessed the prevalence of thyroid function disorders and presence of thyroid antibodies in 5047 subjects (81% females and 19% males). Individuals previously diagnosed or treated for thyroid disease were excluded from the study. TSH, Free T4, total T3, Anti TPO(thyroid peroxidase) and anti TG (thyroglobulin) were measured with electrochemiluminescence method with Cobas 6000 Roche Diagnostics. We calculated the frequency of thyroid antibodies and the abnormal thyroid function. Statistical analysis was performed to see if there was a difference between individuals with positive antibodies and those negative for antibodies. Results: 91 % (4596) of subjects resulted euthyroid. We found a low prevalence of overt thyroid dysfunction (hyperthyroidism 0.48% and hypothyroidism 1.69%). The rates of subclinical hypothyroidism and hyperthyroidism were 5.5% and 1.4% respectively. The prevalence of positive thyroid antibodies, at least one of them was 28% in females and 14% in males (2:1 ratio). 97.3 % of subjects who testet negative for antibodies had normal thyroid function compared to 73.5% in antibodies positive group. There was a significant difference for subclinical hypothyroidism and other thyroid disorders between antibodies positive group and antibodies negative group (p value <0.0000119% of individuals(from 5047 examined) had normal thyroid function and resulted positive for anti TPO or anti TG. Conclusions: Undiagnosed biochemical thyroid dysfunctions were common in subjects living in a mild to moderate iodine-deficient area especially subclinical hypothyroidism. TSH level correlated well with the presence of antibodies resulting in significant difference in thyroid function between 2 groups. We found a high prevalence (19%) of thyroid antibodies in euthyroid subjects. TPO antibodies in euthyroid subjects can be used to identify subjects with increased risk for hypothyroidism such as women who are pregnant (to predict first trimester or postpartum thyroid dysfunction), patients with other autoimmune diseases, subjects on drugs like amiodarone or relatives of patients with autoimmune thyroid diseases.

Risk Factors for Postpartum Thyroid Dysfunction in Euthyroid Women Prior to Pregnancy.

Thyroid dysfunction is common during the postpartum and the predisposing factors for its development are considered specific for the population studied. The aim of this study was to evaluate the risk factors for the occurrence of postpartum thyroid dysfunction (PPTD) in euthyroid women prior to pregnancy. Forty-five women with PPTD and 55 age-matched euthyroid postpartum women from Plovdiv, Bulgaria were included in the study. TSH, FT4, FT3, TPOAb, TgAb, TRAb were measured and ultrasound evaluation of the thyroid was performed in the first trimester of pregnancy and during the postpartum. The study found higher risk of developing PPTD in women with family history of thyroid disease (OR 4.42; 95% CI 1.87,10.43), smokers (OR 4.01; 95% CI 1.72,9.35), personal history of autoimmune thyroid disease (OR 5.37; 95% CI 1.15,28.53), positive TPOAb (OR 18.12; 95% CI 4.93,66.65) and thyroid US hypoechogenicity during early pregnancy (OR 6.39; 95% CI 2.53,16.12) and those who needed levothyroxine during pregnancy (OR 3.69; 95% CI 1.28,10.61). BMI before pregnancy was significantly lower in women with PPTD than in euthyroid postpartum women (22.80±0.55 vs 26.25±0.97, p=0.013). The multivariate logistic regression analysis identified as most important independent risk factors for PPTD occurrence the TPOAb positivity during early pregnancy, family history of thyroid disease, smoking and lower BMI before pregnancy. Our data suggest that in the population studied several factors are associated with an increased risk of PPTD and screening for thyroid disorders among those women can be beneficial.

Postpartum thyroid dysfunction in women with autoimmune thyroiditis

Introduction: Autoimmune thyroiditis (AIT) is a predisposing factor for developing postpartum thyroid dysfunction (PPTD).Aim: To study the characteristics of PPTD in women with AIT.Methods: Thirty-eight women with pre-existing AIT were included in the study. Thyroid-stimulating hormone, free triiodthyronine, free thyroxine, thyroid peroxidase antibodies, thyroglobulin antibodies were measured and ultrasound evaluation of the thyroid gland was performed in the first trimester of pregnancy and during the first year following delivery.Results: Thyroid dysfunction was recognized in 68.4% of the patients – 28.9% presented with hypothyroidism and 39.5 % with thyrotoxicosis. The immunological and morphological parameters did not differ between euthyroid women and those with thyroid dysfunction. At the end of the postpartum period restoration of euthyroid state (being on the treatment before pregnancy) was observed in 15.4% of patients with PPTD, while 84.6% required increase of the levothyroxine dose. The analysis found a significantly lower volume of the thyroid gland, shorter duration of the disease, a lower dose of levothyroxine before and during gestation in patients with impaired thyroid function at the end of the postpartum period.Conclusion: The risk of PPTD in women with AIT predating pregnancy is higher among women with preserved thyroid functional capacity motivating a thorough assessment of thyroid hormone levels and close follow-up of those women during the postpartum period.

Recurrent Hyperthyroidism Following Postpartum Thyroiditis in a Woman with Hashimoto's Thyroiditis

Postpartum thyroid dysfunction occurs in 5-10% of women within one year after delivery. Women with hypothyroidism antedating pregnancy are at high risk for postpartum thyroiditis and should be closely monitored during the first year post-partum. Here, we report a case of recurrent hyperthyroidism between two episodes of postpartum thyroiditis in a w oman diagnosed with subclinical hypothyroidism prior to pregnancy. It is of particular interest that spontaneously remitting hyperthyroidis m as a sequela of postpartum thyroiditis can occur.

Anti-thyroid peroxidase antibody positivity during early pregnancy is associated with pregnancy complications and maternal morbidity in later life.

Aims:We assessed the impact of detecting anti-thyroid peroxidase antibodies (anti-TPO-Ab) in the first trimester of pregnancy on pregnancy outcomes and maternal thyroid function during the postpartum period.Materials and Methods:In a prospective study consisting 400 pregnant women (8-12 weeks pregnant) were screened for their thyroid profile and followed-up to 12 weeks postpartum. Patients with abnormal thyroid function at 12 weeks postpartum were further followed-up with repeated assessment of thyroid stimulating hormone (TSH) and serum-free thyroxine-4 levels at 8 weeks interval up to 12 months postpartum.Results:11.5% of the subjects were positive for anti-TPO-Ab who had mean TSH level of 2.31 μIU/ml, which was significantly (P- 0.0001) higher than pregnant women negative for anti-TPO-Ab (1.73 μIU/ml). Increased incidence of miscarriage was observed in anti-TPO positive mothers when compared to antibody negative mothers. Postpartum thyroid dysfunction developed in 4.7% cases at 12 weeks, among them antibody positivity was observed in 81.25% of subjects. In 18.75% mothers positive for anti-TPO-Ab, the thyroid dysfunction persisted up to 12 months postpartum.Conclusions:Thyroid antibodies detected in early pregnancy seems to be predicting pregnancy complications and later maternal thyroid disease related morbidity.

Clark T. Sawin historical vignette: what do criminology, Harry Houdini, and King George V have in common with postpartum thyroid dysfunction?

The history of postpartum thyroid dysfunction (PPTD) dates back almost two millennia, when Soranus of Ephesus, who practiced obstetrics and neonatology, observed swelling in the necks (presumably goiters) of women after pregnancy. The next reference to PPTD appeared in artwork more than 1000 years later, with many portraits illustrating women with goiter while holding infants. In the early to mid-19th century, Caleb Hillier Parry and Armand Trousseau described postpartum hyperthyroidism, while in the late 1800s, Sir Horatio Bryan Donkin reported the first patient with postpartum hypothyroidism. The modern era of PPTD began with the description in the late 1940s by H.E.W. Roberton of women after delivery reporting hypothyroid symptoms and responding to thyroid extract. The immunologic influence on PPTD was recognized initially by Parker and Beierwaltes in the early 1960s, and the clinical variability and natural history were carefully documented by numerous investigators in the 1970s-1980s. The past two decades have seen further refinements in understanding the prevalence, etiology, and treatment of PPTD. Yet to be determined is the role of screening as a cost-effective measure.

A longitudinal study of thyroid autoantibodies in pregnancy: the importance of test timing.

Thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibodies (TGAb) are frequently measured to investigate thyroid dysfunction in pregnancy. Despite the recognized fall of these autoantibodies in pregnancy, there is limited guidance on the timing of such testing. We assessed optimal test timing of TPOAb/TGAb for the detection of Hashimoto's thyroiditis and post-partum thyroid dysfunction (PPTD). Prospective longitudinal study with recruitment in Trimester 1. Healthy women ≤13weeks' gestation from Mercy Hospital for Women, a tertiary obstetric hospital in Melbourne. Serum TPOAb, TGAb, TSH and fT4 were measured at Trimester 1 (T1), Trimester 2(T2), Trimester 3(T3) and postpartum (PP) in each participant. Post-partum thyroid dysfunction (PPTD) was defined if TSH deviated from the assay's nonpregnant reference interval. Longitudinal random-effect logistic regression was used to investigate the association between time and positive/negative thyroid autoantibody status. Samples from 140 women at T1 (12·0: 10·3-13·0) (median: IQR weeks' gestation); 95 at T2 (24·3: 23·0-25·9), 79 at T3 (35·9: 34·8-36·7) and 83 at PP (12·4: 10·8-14·6weeks post-partum) were attained. At T1, 13 (9%) and 15 (11%) women had positive TPOAb and TGAb, respectively. The odds of having a positive TPOAb were 96% lower at T2 [OR=0·04 (95% CI: 0·02-0·8; P=0·03)] and 97% lower at T3 [OR=0·03 (95% CI: 0·001-0·6; P=0·02)] than at T1. Similarly, the odds of having a positive TGAb were 99·4% lower [OR=0·006 (95% CI: 0-0·3; P=0·01)] at T2, and 99·5% lower [OR=0·005 (95% CI: 0-0·4; P=0·02)] at T3 than at T1. The ROC analysis diagnostic ORs for a positive TPOAb and/or TGAb to predict PPTD were 7·8 (95% CI: 2·2-27·6), 1·2 (95% CI: 0-8·9), 2·0 (95% CI: 0-16·8), and 12·2 (95% CI: 3·3-44·9) at T1, T2, T3 and post-partum, respectively. A significant proportion of pregnant women lose their thyroid autoantibody positivity after T1. The gestation-dependent loss of TPOAb/TGAb positivity and reduction in diagnostic accuracy for predicting PPTD limits the value of testing at T2 and T3.

Differentiation of Postpartum Graves' Thyrotoxicosis from Postpartum Destructive Thyrotoxicosis Using Antithyrotropin Receptor Antibodies and Thyroid Blood Flow

Postpartum thyroid dysfunction occurs in approximately 5-10% of women in the general population within one year of delivery. Differentiation of postpartum Graves' thyrotoxicosis (PPGr) from postpartum destructive thyrotoxicosis (PPDT) is essential because of the difference in treatment measures between the two. However, it is sometimes difficult because radioactive iodine uptake is contraindicated when patients are lactating. We examined the usefulness of determining the time of onset postpartum and measurement of antithyrotropin (anti-TSH) receptor antibodies and thyroid blood flow. Forty-two patients with newly developed thyrotoxicosis after delivery were examined: 18 had Graves' disease and 24 had destructive thyrotoxicosis. Serum free thyroxine (fT4), free triiodothyronine (fT3), and TSH were measured by chemiluminescent immunoassays. Anti-TSH receptor antibodies (TRAb), antithyroglobulin antibodies (TgAb), and antithyroid peroxidase antibodies (TPOAb) were measured by the Elecsys electrochemiluminescence immunoassay. Thyroid volume and blood flow (TBF) were measured quantitatively by color flow Doppler ultrasonography. Onset of thyrotoxicosis was distributed from 2 to 12 months postpartum. Twelve (85.7%) of 14 patients who developed thyrotoxicosis at three months or earlier after delivery had PPDT. On the other hand, all 11 patients who developed thyrotoxicosis at 6.5 months or later had PPGr. All patients with PPGr had positive TRAb (14.9±14.9 IU/L, mean±standard deviation (SD)) and all patients with PPDT had negative TRAb (0.1±0.3 IU/L, p<0.0001). Fifteen (83.3%) of 18 PPGr patients had high TBF of more than 4.0% (8.9±4.4), and all PPDT patients had low TBF of <4.0% (1.6±1.0, p<0.0001). The fT3/fT4 ratio was higher in PPGr (64.0±23.9) than in PPDT (38.9±13.1, p<0.0002), but absolute values overlapped between the two. Early onset of thyrotoxicosis postpartum was associated mainly with PPDT, and a late onset was suggestive of PPGr. Positive TRAb and high TBF >4.0% are indicators of postpartum onset of Graves' disease.

Preventing, identifying and managing thyroid deficiency in prenatal practice

Despite the lack of consensus among groups issuing recent guidelines, it is possible to identify options that are available for prenatal practitioners. Examples include the following: iodine supplements to protect against hypothyroidism; adjusting l-thyroxine dosage upward in women with previously diagnosed hypothyroidism to account for increased pregnancy needs; and screening for undetected thyroid deficiency via targeted questions and/or thyroid-stimulating hormone testing. Decision-making about thyroid status requires access to reliable, trimester-specific normative data for both thyroid-stimulating hormone and free thyroxine, as well as an understanding of the impact of human chorionic gonadotropin on thyroid function, especially during the first trimester. Continuity of care is enhanced by systematic follow-up postpartum, including attention to postpartum thyroid dysfunction that often occurs among women with raised antibody levels.

Increased thyroid autoimmunity among women with multiple sclerosis in the postpartum setting

Background: Multiple sclerosis (MS) patients are predisposed to thyroid abnormalities, but the risk for pregnancy-related thyroid pathology among MS patients has not been evaluated. Objectives: The objectives of this research are to prospectively evaluate the prevalence of thyroid autoimmunity among MS patients in relation to pregnancy, and to investigate its impact on pregnancy outcome, postpartum depression and fatigue. Methods: Forty-six pregnant MS patients underwent repeat testing for serum thyroid antibodies (Abs), clinical evaluation and thyroid hormone measurement. Results were compared to 35 age-matched healthy mothers. Results: At six months postpartum 35.3% of MS patients presented elevated levels of thyroid Abs compared to 5.7% of controls, p = 0.01. Mean thyroid Ab concentrations among MS patients were significantly reduced during pregnancy and returned to maximal levels at six months postpartum. The proportion of individuals with postpartum thyroid dysfunction did not differ significantly between MS patients and healthy controls (3.4% vs 2.9%, p = 1.00). Elevated thyroid Ab levels did not increase the risk for adverse pregnancy outcome, fatigue or postpartum depression. Conclusions: Considering the tendency of MS mothers to develop thyroid autoimmunity postpartum and in association to treatments, we recommend screening MS patients for thyroid dysfunction (TSH) during early pregnancy and after delivery.

The First Case of Association Between Postpartum Thyroiditis and Thyroid Hormone Resistance in an Italian Patient Showing a Novel p.V283A THRB Mutation

Postpartum thyroiditis (PPT) is characterized by the development of postpartum thyroid dysfunction, which may occur up to 12 months after delivery. The syndrome usually presents with transient thyrotoxicosis, followed by transient hypothyroidism. The association of this condition with resistance to thyroid hormones (RTH) has never been described. In this report, we describe a 30-year-old patient affected by RTH due to a novel p.V283A thyroid hormone receptor-β (THRB) heterozygous mutation in exon 8, which affects the ligand-binding domain, never before described in literature. A simple polymorphism was excluded through screening of 100 healthy controls. The patient became pregnant twice (in 2008 and in 2009) and developed PPT after both deliveries. Two months after her first pregnancy and one month after her second pregnancy, she presented with severe endogenous thyrotoxicosis and concomitant suppressed thyrotropin (TSH) levels, which represents an unusual finding in patients affected by RTH. Other causes of hyperthyroidism were excluded. After the hyperthyroid phase, she became hypothyroid (TSH >75 mU/L and low free-thyroxine and free-tri-iodothyronine levels), and eventually returned to her usual euthyroid status. During the course of PPT, no specific treatment was required, except for β-blockers used to treat tachycardia during the hyperthyroid phase. We report a unique case of a woman affected by RTH, due to a novel mutation V283A in THRB, who experienced PPT with a severe thyrotoxic phase after both her pregnancies. The association between RTH and PPT has never been reported in the literature. In particular, the marked suppression of TSH occurring when levels of TH are particularly elevated is not a frequent condition during RTH.

Thyroid function tests at delivery and risk for postpartum depressive symptoms

Postpartum depression (PPD) is a common childbirth complication, which can have negative effects on both the newly delivered woman and her family. This condition is underdiagnosed and inadequately treated, while a biological diagnostic test is not yet available. Furthermore, postpartum thyroid dysfunction is common among new mothers, and some evidence point to an association between PPD and thyroid function disturbances. The aim of this study was to evaluate the possible association between serum levels of thyroid hormones at the time of delivery, and the later development of depressive symptoms, using data from a population based cohort of Swedish women. Blood samples were collected during delivery from 347 participating women, delivering at Uppsala University Hospital. The participating women filled in at least one of three structured questionnaires, containing the Edinburgh Postnatal Depression Scale (EPDS), at five days, six weeks and six months postpartum. A cut-off of 12 or more was applied on the EPDS, to identify cases of self-reported PPD and controls. Using a binary logistic regression model (adjusting for previous psychiatric contact, smoking during pregnancy, pre-pregnancy body mass index (BMI) and sleep), having a thyroid stimulating hormone (TSH) level over the clinical cut-off level of 4.0 mU/L was associated with increased risk for depressive symptoms at six months postpartum (OR 11.30, 95% CI 1.93-66.11). A ROC analysis revealed that the predictive variable (PV) had significant predictive ability for PPD at 6 months postpartum, given that the AUC was 0.764, and at a PV cut-off value of 6.33, the sensitivity and specificity were 76.2% and 69.4%, respectively. If these findings are replicated in future studies, they can have important clinical implications, since TSH determination is an inexpensive routine blood test, and its inclusion in a biological screening test for PPD involving other parameters would be tempting.

Thyroid dysfunction in hyperemesis gravidarum: a study in Turkish pregnant women

In this study we investigate the possible relation of thyroid dysfunction and thyroid antibodies to hyperemesis gravidarum. Thirty-seven patients with hyperemesis gravidarum and 33 healthy controls have been included in this study. Thyroid dysfunction was significantly more common than in controls (38% vs 6%, p=0.002). Thyroglobulin antibodies were also significantly more common in patients with hyperemesis gravidarum than controls (54 IU/mL vs. 14 IU/mL, p=0.03). Hyperemesis gravidarum can be a risk factor for postpartum thyroid dysfunction. Thyroid antibodies must be checked in the hyperemesis population in an endemic goitre region and/or iodine replacement regions.

Low urinary iodine postpartum is associated with hypothyroid postpartum thyroid dysfunction and predicts long-term hypothyroidism

Postpartum thyroid dysfunction (PPTD) is characterized by an early hyperthyroid phase followed, with peak prevalence at 6 months, by a hypothyroid phase which carries a risk of long-term hypothyroidism. Iodine has a major effect on thyroid function. Western Australia has previously been shown to be iodine replete. To examine the iodine status of women with and without PPTD and the relationship of iodine status postpartum with long-term hypothyroidism. Case-control with follow-up. A total of 149 women at 6 months postpartum (74 PPTD, 75 controls) with 98 (46 PPTD, 52 controls) followed up at 12 years. Urinary iodine concentration (UIC) and thyroid function at 6 months postpartum; thyroid function at 12-year follow-up. At 6 months postpartum, median UIC (quartiles) for observed TSH ranges were: for TSH < 0·4 mU/l 130·0 μg/l (82·0, 170·0); for TSH 0·4-4·0 mU/l 123·0 μg/l (80·5, 168·0); for TSH > 4·0 mU/l 85·0 μg/l (40·0, 141·5), P = 0·018. The odds ratio (OR) of hypothyroid PPTD with each unit of decreasing log iodine was 2·54, (95%CI: 1·47, 4·35), and with UIC < 50 μg/l, OR 4·22, (95%CI: 1·54, 11·55). In the long term, decreased log UIC significantly predicted hypothyroidism at 12-year follow-up (P = 0·002); as did UIC < 100 μg/l (P = 0·03) and UIC < 50 μg/l (P = 0·02). The association was independent of antibody status. Low UIC measured at 6 months postpartum is associated with hypothyroid PPTD and independently predicts long-term hypothyroidism. We believe that it results from more severe preceding destructive thyroiditis, with discharge of thyroidal iodine, and thereby predicts a greater risk of long-term hypothyroidism.

The Continuing Saga of Postpartum Thyroiditis

Postpartum thyroiditis (PPT) is characterized by the development of postpartum thyroid dysfunction (PPTD), which may occur up to 12 months after delivery. Usually the syndrome presents as transient hyperthyroidism (median time of onset, 13 wk) followed by transient hypothyroidism (median time of onset, 19 wk). Clinically, women are relatively asymptomatic during the hyperthyroid phase, although some may notice palpitations requiring treatment with -adrenergic blocking agents. In contrast, patients experience persistent and troublesome symptoms related to the hypothyroid period, which usually must be treated with levothyroxine, normally for up to 1 yr (1, 2). Several studies from different countries have shown that about 12–61% of women who develop postpartum hypothyroidism go on to a permanent hypothyroid state when assessed 1 yr or more after delivery (2–4); these women then require lifelong levothyroxine replacement therapy. In those women who do not develop permanent hypothyroidism, the chance of experiencing a recurrence of PPTD after a previous episode is around 70% (5). The incidence of PPTD has been the subject of much debate. Although most reviews cite a range from 4–9% (6), there is considerable variation in these figures due to sample bias, frequency of blood sampling, and definition of the syndrome. For example, an incidence of 16.7% quoted by Fung et al. (2) was later shown to be erroneous due to the inclusion of the large denominator of thyroid peroxidase (TPO) antibody-negative persons used in the calculation. Nevertheless, the wider incidence has ranges from 1.1 to 21.1%. PPTD is an immunological disorder occurring more frequently in women with certain human leukocyte antigen haplotypes and being usually characterized by the presence of circulating TPO antibodies (7). Indeed, the condition occurs in up to 50% of women found to be TPO antibody positive at the end of the first trimester of gestation (i.e. before the titers start to decline during pregnancy). The other 50% of TPO antibody-positive women who have no thyroid dysfunction are considered to have PPT but not PPTD. Furthermore, there is evidence that the TPO antibody titer at 16 wk gestation is related to the severity of the PPTD (8). The prospective study of PPT by Stagnaro-Green et al. (9) is an important contribution to the epidemiology of postpartum thyroid disease and adds to the debate in several ways. They took advantage of a previously reported study of screening for thyroid function in pregnancy that examined 4562 pregnant women from southern Italy (Puglia) in the first trimester (10). In that study, women were randomly assigned to a universal screening group or a case-finding group. In addition, women in both groups were grouped as high risk if they had one of the following: family history of autoimmune thyroid disease, presence of goiter, signs and symptoms suggestive for thyroid dysfunction, personal history for type 1 diabetes or other autoimmune disease, and history of neck irradiation, previous miscarriages, or preterm deliveries. A total of 4384 women were tested at 6 and 12 months postpartum for thyroid function (TSH and TPO antibodies), with free T4 being measured if hyperthyroidism was suspected. They were also screened in the first trimester, and those with thyroid dysfunction at that time were not studied further for this analysis. PPTD was defined by the usual criteria (2). The incidence of PPT was low at 3.9%. This figure should be compared with two studies from northern Italy that reported incidences of 8.7 and 18%, respectively (11, 12). However the base population in both studies did not exceed 400. Although women who were TPO antibody positive or women in the high-risk groups reported by Stagnaro-Green et al. (9) were significantly more likely to