Publication:

Clinical impact of thymosin alpha 1 as an adjuvant in enhancing frozen embryo transfer outcomes: a self-controlled study

Background Endometrial immune milieu when studied appeared to be dysregulated in 81.7% of women with recurrent implantation failure (RIF). Thymosin alpha 1, a small peptide secreted from the thymus gland has the ability to favourably alter the maternal immune milieu conducive for embryo implantation and maintenance of pregnancy.  This study plans to evaluate the impact of empirical use of Thymosin alpha 1 as an adjuvant in improving the pregnancy outcomes in women with more than two failed frozen embryo transfers (FETs).

Methods Women who experienced two prior failed FETs despite good-quality embryos underwent endometrial preparation for their next FET cycle using hormone replacement therapy (HRT) supplemented with exogenous Thymosin alpha 1. Pregnancy outcomes were then compared to those from the immediately preceding cycle.

Results In this cohort of 27 patients with two prior FET failures, addition of Thymosin alpha 1 in the subsequent FET cycle significantly improved implantation rates (63.4%; p<0.001) biochemical and clinical pregnancy rates (66.7%; p<0.001), and ongoing pregnancy rates (59.3%; p<0.001). No significant difference was observed in mean Thymosin dose between pregnant and non-pregnant women (22 mg vs. 20.3 mg; p=0.373).

Conclusions The study provides encouraging evidence that thymosin alpha 1 could be an useful adjunct for improving pregnancy outcomes in women with RIF.