A woman's immune system is suppressed during pregnancy, but becomes more active following delivery of a baby. If you have a genetic tendency toward autoimmune thyroid problems, you may experience a painless inflammation of the thyroid as your immune system becomes more active in the months after delivery, even if you have no history of thyroid problems before or during pregnancy.
In its early stages, hyperthyroid symptoms may occur if excessive amounts of thyroid hormone leak into the bloodstream from your inflamed thyroid gland. Later on, when the thyroid's supply of hormones is exhausted, blood levels of these hormones often fall below normal and symptoms of hypothyroidism may appear.
Beta adrenergic blocking drugs like propranalol, atenolol, and metoprolol are usually enough to control the symptoms if you develop hyperthyroidism in the early weeks of this condition. If your thyroid fails after several months, supplementary thyroid hormone tablets can be given to maintain blood levels in the normal range.
Although complete recovery is common, about one-third of all women with postpartum thyroiditis progress to permanent hypothyroidism within three to four years, and require life-long treatment.