Hypothyroidism

Incidence 1% in general population; 0.3% in pregnant women (1,2). General screening of obstetric patients reveals an incidence of 2.5% of elevated serum TSH (2). There is an increased incidence with concurrent autoimmune disease, that is, 5% to 8% incidence in patients with type 1 diabetes (3). Up to 25% of patients with type I diabetes develop postpartum thyroid dysfunction (3). In the United States, 10% to 15% of pregnant women are iodine deficient (urinary iodine concentration <5 mg/dL) (4).