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

OBJECTIVE

To study the beneficial effects of thyroid replacement therapy (TRT) on pregnancy outcomes in patients with subclinical hypothyroidism (SCl hypoT) with respect to thyroid peroxidase (TPO) autoantibodies.

DESIGN

Retrospective study of 706 patients.

SETTING

Not applicable.

PATIENTS

The study evaluated 706 patients, who were divided into 3 cohorts: euthyroid patients, with pre-in vitro fertilization thyroid-stimulating hormone levels of <2.5 μIU/mL; patients with SCl hypoT, defined as thyroid-stimulating hormone levels of >2.5 μIU/mL and <4 μIU/mL, who were not treated; and patients with SCl hypoT who received TRT. The 3 cohorts were further subclassified into 2 groups, each based on TPO antibody levels.

INTERVENTIONS

The cohorts were compared for the effects of TRT on pregnancy outcomes.

MAIN OUTCOME MEASURES

Identification of effects of TRT on assisted reproductive technology outcomes.

RESULTS

Patients with SCl hypoT had significantly fewer positive pregnancy outcomes than euthyroid patients. Importantly, low-dose TRT was found to be beneficial in improving IVF success and pregnancy outcomes in patients with SCl hypoT. The original cohort of patients, further classified into 2 subgroups on the basis of antithyroid (TPO) antibodies, showed that low-dose TRT was associated with improved pregnancy outcomes in women with SCl hypoT and TPO-positive antibodies.

CONCLUSIONS

Our findings demonstrate that low-dose TRT may be beneficial in improving in vitro fertilization success and pregnancy outcomes in women with SCl hypoT and TPO-positive antibodies.