These women may include those who Have symptoms Come from an area where moderate to severe iodine insufficiency occurs Have a family or personal history of thyroid disorders Have type 1 diabetes Have a history of infertility, preterm delivery, or miscarriage Have had head or neck radiation therapy Are morbidly obese (BMI > 40 kg / m2) Are > 30 years Ultrasonography Most obstetricians recommend at least one ultrasound examination during each pregnancy, ideally between 16 and 20 weeks, when estimated delivery date (EDD) can still be confirmed fairly accurately and when placental location and fetal anatomy can be evaluated.