Hypothyroidism, Oxidative Stress and Reproduction

In women, both hyperand hypo-thyroidism may result in menstrual disturbances. In hyperthyroidism the most common manifestations are simple oligomenorrhea and anovulatory cycles. Hypothyroidism results in changes in cycle length, amount of bleeding, and usually is associated with abnormal menstrual cycles characterized mainly by polymenorrhea and anovulatory cycles (Krassas et al., 1999). Also subclinical hypothyroxinemia can be associated with short luteal phase and insufficient progesterone secretion (Bohnet et al., 1981); similar pictures are present in a variety of situations characterized by low T3 levels (malnutrition, chronic illness, exercise), known as “nonthyroidal illness” (De Groot, 2006).