Prolonged APTT and autoimmune overt hypothyroidism identified postpartum: a case report

INTRODUCTION: Thyroid disorders have been linked to abnormalities in the coagulation system, and a hypocoagulant state has been proposed in hypothyroidism. The assessment of thyroid function is, however, not routinely recommended as part of the assessment for coagulation disorders. CASE PRESENTATION: We present a 32-year-old woman who had no history of thyroid disease and who recently gave birth preterm because of severe preeclampsia and intrauterine growth restriction. Due to severe placental dysfunction, she underwent a routine biochemical assessment of the coagulation system 6 months postpartum, and a prolonged activated partial thromboplastin time (APTT) (43 s) was identified along with a low level of coagulation factor VIII (0.44 IU/mL), and a low level of von Willebrand factor (vWF) antigen (0.35 IU/mL), vWF activity (0.38 IU/mL) as well as reduced generation of thrombin. The assessment of thyroid function in the patient identified autoimmune, overt hypothyroidism with a thyroid-stimulating hormone (TSH) concentration of 139 mIU/L, low levels of the peripheral thyroid hormones (total thyroxine: 43 nmol/L, total triiodothyronine: 0.9 nmol/L), and high levels of thyroid peroxidase antibodies (296 U/mL) as well as thyroglobulin antibodies (927 U/mL). CONCLUSION: In this case, prolonged APTT provided a diagnostic clue for the assessment of thyroid function in a young woman with a recent history of severe placental dysfunction. The identification of autoimmune, overt hypothyroidism emphasizes that measurement of TSH may be of clinical importance in cases of unexplained prolonged APTT or other biochemical signs of abnormalities in the coagulation system. ESTABLISHED FACTS: Hypothyroidism has been associated with alterations of the coagulation system suggesting a hypocoagulant state. At present, measurement of thyroid-stimulating hormone is not routinely recommended as part of the assessment for coagulation disorders. NOVEL INSIGHTS: In this case, biochemical assessment of the coagulation system was routinely performed following a pregnancy complicated by severe placental dysfunction. Overt hypothyroidism of autoimmune origin was identified secondary to prolonged activated partial thromboplastin time (APTT) postpartum along with low levels of coagulation factor VIII, von Willebrand factor, and thrombin generation. Measurement of thyroid-stimulating hormone may be considered in cases of unexplained prolonged APTT

Biochemical markers of renal function and maternal hypothyroidism in early pregnancy

OBJECTIVE: The physiological adaptations during a normal pregnancy affect renal and thyroid function and levels of associated biochemical markers. An association between cystatin C (CysC), creatinine, and thyroid function has been considered in nonpregnant individuals but not in pregnant women specifically.METHODS: Cohort study within the North Denmark Region Pregnancy Cohort (2011-2015) with assessment of thyroid function and autoantibodies (ADVIA Centaur XPT, Siemens Healthineers) in serum residues from the early pregnancy. Consecutive samples (n = 1112) were selected for measurement of CysC and creatinine (Atellica CH 930, Siemens Healthineers), and results were linked to information in Danish nationwide registers for (i) establishment of pregnancy-specific reference intervals for CysC and creatinine and (ii) evaluation of the prevalence of maternal hypothyroidism in early pregnancy according to levels of CysC and creatinine.RESULTS: The established reference intervals (2.5-97.5 percentiles) differed by week of pregnancy (week 4-8, 9-11, 12-15) and were CysC: 0.58-0.92 mg/L; 0.54-0.91 mg/L; 0.52-0.86 mg/L; creatinine: 46.9-73.0 µmol/L; 42.0-68.4 µmol/L; 38.8-66.4 µmol/L. The prevalence of maternal autoimmune hypothyroidism in early pregnancy differed by the level of CysC and creatinine (&lt;25th percentile; 25th-75th percentile; &gt;75th percentile) and was for CysC 1.7%, 3.8%, 7.4% and for creatinine 2.5%, 4.1%, 7.1%.CONCLUSIONS: Reference intervals for CysC and creatinine were dynamic in early pregnancy and decreased with increasing gestational age. Furthermore, higher levels of CysC and creatinine associated with a higher prevalence of maternal autoimmune hypothyroidism. Results encourage considerations on the underlying mechanisms for the association between markers of renal and thyroid function.</p

Maternal hypothyroidism and the risk of preeclampsia: a Danish national and regional study

Abstract Background Maternal hypothyroidism in pregnancy has been proposed to increase the risk of preeclampsia, but uncertainties persist regarding the underlying causal mechanisms. Thus, it remains unclear if an increased risk of preeclampsia in hypothyroid pregnant women is caused by the lack of thyroid hormones or by the autoimmunity per se. Methods We conducted a retrospective study of two pregnancy cohorts in the Danish population. The nationwide cohort (n = 1,014,775) was register-based and included all singleton pregnancies in Denmark from 1999–2015. The regional cohort (n = 14,573) included the biochemical measurement of thyroid stimulating hormone (TSH), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (Tg-Ab) (ADVIA Centaur XPT, Siemens Healthineers) among pregnant women in The North Denmark Region from 2011–2015 who had a blood sample drawn in early pregnancy as part of routine prenatal screening for chromosomal anomalies. The associations between diagnosed and biochemically assessed hypothyroidism and a diagnosis of preeclampsia were evaluated using logistic regression (adjusted odds ratio (aOR) with 95% confidence interval (CI)) adjusting for potential confounders, such as maternal age, diabetes, and parity. Results In the nationwide cohort, 2.2% of pregnant women with no history of hypothyroidism (reference group (ref.)) were diagnosed with preeclampsia, whereas the prevalence was 3.0% among pregnant women with hypothyroidism (aOR 1.3 (95% CI: 1.2–1.4)) and 4.2% among women with newly diagnosed hypothyroidism in the pregnancy (aOR 1.6 (95% CI: 1.3–2.0)). In the regional cohort, 2.3% of women with early pregnancy TSH  60 U/mL) or Tg-Ab (> 33 U/mL) in early pregnancy (aOR 0.86 (95% CI: 0.6–1.2)). Conclusions In two large cohorts of Danish pregnant women, maternal hypothyroidism was consistently associated with a higher risk of preeclampsia. Biochemical assessment of maternal thyroid function revealed that the severity of hypothyroidism was important. Furthermore, results did not support an association between thyroid autoimmunity per se and preeclampsia