The influence of thyroid autoimmunity on pregnancy outcome in infertile women: a prospective study

Abstract

Thyroid dysfunction and thyroid autoimmunity (TAI) have been reported to be linked to infertility, pregnancy loss and preterm birth. Infertile women undergoing assisted reproductive technology are recommended to maintain thyroid stimulating hormone (TSH) levels below 2.5 μIU/mL. It is unclear, however, whether levothyroxine (L-T4) treatment decreases the effects of TAI on fertility and pregnancy outcome in infertile women. We therefore aimed to clarify the influence of TAI on pregnancy undergoing L-T4 treatment for hypothyroidism. Prospectively recruited to this study were the 595 infertile women who visited the Utsunomiya Ladies Clinic between January 2013 and December 2015. Five patients with Graves' disease were excluded. Clinical profiles of 590 women were as follows: proportion of SCH = 19.6%, thyroid peroxidase antibody (TPOAb) positivity = 10.4%, and thyroglobulin antibody (TgAb) positivity = 15.1%. Fertility was not affected by any thyroid-associated factors. Regarding pregnancy outcomes, TPOAb titers were significantly higher in women who had miscarriage than in those progressed to delivery (46.4 ± 114.1 vs. 18.9 ± 54.6 IU/mL, p = 0.039), notably in those undergoing intrauterine insemination (p = 0.046) and in vitro fertilization (p = 0.023). Multivariate logistic regression analysis revealed that higher age (odds ratio 26.4, p < 0.001) and higher TPOAb titer (odds ratio 11.8, p = 0.043) were risk factors for miscarriage. Higher TPOAb titer should be considered as one of the risk factors for miscarriage in infertile women, even if they have been treated with L-T4 for hypothyroidism.

Thyroid Autoimmunity in Female Infertility and Assisted Reproductive Technology Outcome

“…This links the miscarriage to an abnormal immune response rather than to subsequent mild thyroid failure (74). Also, in a prospective study involving 590 infertile hypothyroid women treated with LT4, to maintain TSH levels below 2.5 mIU/mL, higher TPOAb titer was one of the risk factors for miscarriage, after IUI and IVF despite appropriate treatment (75). Among 194 euthyroid women undergoing IVF, the 60 with TPOAb/Tg Ab showed lower clinical pregnancy and live birth rate when confronted with controls.…”

Positive effects of thyroid replacement therapy on assisted reproductive technology outcomes in women with subclinical hypothyroidism with positive thyroid peroxidase autoantibodies

“…Recent studies suggest that thyroid autoimmunity may adversely impact pregnancy outcomes ( 22 , 23 ). Although the adverse effects of antithyroid antibodies have been well studied in hypothyroid pregnant women, their effects in euthyroid women and in women with SCl hypoT are not well evaluated.…”

Association between serum vitamin D level during pregnancy and recurrent spontaneous abortion: A systematic review and meta‐analysis

“…The mechanism might be that the decrease in vitamin D levels caused an increase in anti‐TPO levels 43 . And high anti‐TPO levels are a risk factor for early miscarriage 44,45 . Therefore, VDD might cause a rise in anti‐TPO synthesis and lead to RSA.…”

“…43 And high anti-TPO levels are a risk factor for early miscarriage. 44,45 Therefore, VDD might cause a rise in anti-TPO synthesis and lead to RSA. The maternal-fetal interface was the primary site of immune regulation during pregnancy.…”