Hypothyroidism is becoming increasingly more common in our culture and is impacting younger people, putting women in the reproductive years at increased risk. Chemicals in our environment and high stress lives are probable causes. Undiagnosed hypothyroidism in pregnancy can have devastating health impacts on babies and the postpartum mother. This lecture will cover recommended screening of thyroid disease in the preconception period and early pregnancy, identification of chemical impacts on hypothyroidism, and management of thyroid disease in pregnancy and the postpartum period.