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.

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

Background: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.Materials and methods: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.Results: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.Conclusion: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.

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.

Thyroid disease after pregnancy: postpartum thyroiditis

Postpartum thyroiditis is defined as an exacerbation of autoimmune thyroiditis during the postpartum period (1). Patients do not develop thyroid autoimmunity at the onset of postpartum thyroiditis, but have ‘subclinical autoimmune thyroiditis’ beforehand which is exacerbated after delivery. Typically an exacerbation induces destructive thyrotoxicosis followed by transient hypothyroidism. However, various types of thyroid dysfunction may occur, including Graves’ disease. Therefore, any kind of thyroid dysfunction observed during the postpartum period, is referred to as ‘postpartum thyroid dysfunction’.

Thyroid Peroxidase Antibody and Screening for Postpartum Thyroid Dysfunction

Postpartum thyroid dysfunction (PPTD) is a common disorder which causes considerable morbidity in affected women. The availability of effective treatment for hypothyroid PPTD, the occurrence of the disease in subsequent pregnancies and the need to identify subjects who develop long term hypothyroidism, has prompted discussion about screening for this disorder. There is currently no consensus about screening as investigations hitherto have been variable in their design, definitions and assay frequency and methodology. There is also a lack of consensus about a suitable screening tool although thyroid peroxidase antibody (TPOAb) is a leading contender. We present data about the use of TPOAb in early pregnancy and its value as a screening tool. Although its positive predictive value is moderate, its sensitivity and specificity when used in early pregnancy are comparable or better compared to other times during pregnancy and the postpartum period. Recent studies have also confirmed this strategy to be cost effective and to compare favourably with other screening strategies. We also explore the advantages of universal screening.