RECURRENT PREGNANCY LOSS IN WOMEN WITH HASHIMOTO'S THYROIDITIS WITH CONCURRENT NON-ENDOCRINE AUTOIMMUNE DISORDERS

BACKGROUND: An increased rate of recurrent miscarriage has been described in patients with autoimmune thyroid disease. However, there is a lack of studies that assess the rate of recurrent pregnancy loss (RPL) in patients with Hashimoto's thyroiditis (HT) isolated or with concurrent non-endocrine autoimmune disorders (NEAD). The objective of the study was to assess the rate of recurrent pregnancy loss in patients with HT isolated or accompanied with non-endocrine autoimmune diseases. METHODS: This is a retrospective observational cohort study with systematic review of the NEAD with concurrent HT in an outpatient Endocrinology Unit at a University Hospital. Among the 3480 consecutively examined women with HT, 87 patients met the criteria of RPL and represented the study group. Sixty-five of them had isolated HT and 22 women had HT+NEAD. RESULTS: The rate of RPL in women with HT was 2.1% versus 5.64% observed in women with HT+NEAD (OR=2.78, 95%CI=1.70-4.57; p<0.0001). Upon subdivision, this difference was still evident in euthyroid patients (p<0.0001), while it disappeared in hypothyroid women (p=0.21). RPL did not correlate with the autoantibody concentrations nor in women with isolated HT nor in those with HT+NEAD. The presence of antiphospholipid syndrome (APS) explained RPL in 3/22 (14%) patients with HT+NEAD, the remaining being related to different autoimmune disorders. Interestingly, even subtracting the patients with APS, RPL was more frequent in patients with poly-autoimmunity than in patients with isolated HT (p=0.0013). CONCLUSIONS: The co-presence of NEAD is correlated with a higher risk of RPL in women with HT. The association with APS may explain only a fraction of RPL rate in patients with polyautoimmunity.