Date Time New research highlights importance of thymus in successful pregnancies How the immune system adapts to pregnancies has puzzled scientists for decades. Now, findings from an international group of researchers, led by researchers at Karolinska Institutet in Sweden, reveal important changes that occur in the thymus to prevent miscarriages and gestational diabetes. The results are published in the journal Nature. The thymus is a central organ of the immune system where specialised immune cells called T lymphocytes mature. These cells, commonly referred to as T cells, then migrate into the blood stream and tissues to help combat pathogens and cancer. An important T cell subset, known as a regulatory T cell or Treg, is also produced in the thymus. The main function of a Treg is to help regulate other immune cells.