Repeated pregnancy loss (RPL), defined as two or more spontaneous abortions, may be associated with autoimmune thyroiditis (AT), either isolated or associated with polyautoimmune disorders (PD), which include antiphospholipid syndrome. An increased occurrence of RPL has been reported in patients with isolated AT but very few data are available on the influence of concurrent auto-aggressive disorders on RPL and this represented the aim of our study. A cohort of 1765 consecutively examined women with AT was retrospectively analyzed. Of these, 1501 had isolated AT and 264 had a simultaneous autoimmune disorder. Some 29% of women (516 out of 1765) had an abortion but only 87 (4.93%; median age=28 years) had at least 2 abortions within the first 20 weeks of gestation. RPL rate was highly different when analyzed in women with isolated AT (n=65; 4.33%) and in those with PD (n=22, 8.33%; P=0.0085; OR=2.01). Neither age nor thyroid function were significantly different in these subgroups at the time of first abortion. Similarly, no correlation between the levels of anti-thyroperoxidase antibodies and the number of abortion has been observed in both groups. Analyzing the role of thyroid function as source of bias, RPL rate appeared to be similar in hypothyroid women with isolated AT and with PD (1.8 vs 2.3%; P=ns). On the contrary, among euthyroid women, RPL rate was higher in those with PD than in those with isolated AT (5.3 vs 1.9%; P=0.0035 OR=2.842). In the subgroup of women, in whom successful pregnancy has never been observed (n=15; 17.2%), the occurrence of RPL was again lower in women with isolated AT than in those with PD (P=0.0263). In these latter, the presence of anti- phospholipid antibodies syndrome accounted for just 1/3 of RPL. These data indicated that the risk of repeated pregnancy loss in patients with thyroid autoimmunity is higher in the presence of further autoimmune disorders in an age- and function- independent way.
19 May 2018 - 22 May 2018