Hi thank you for querry, In hypothyriodism following side effect or complication on body may occur. The hypothyroid changes in the heart result in decreased contractility, cardiac enlargement, pericardial effusion, decreased pulse, and decreased cardiac output. In the gastrointestinal (GI) tract, achlorhydria and prolonged intestinal transit time with gastric stasis can occur. Delayed puberty, anovulation, menstrual irregularities, and infertility are common. You should conginue the levothyroxine and for growth problem its a seperate harmone called growth harmone which effect growth. Hope the answe will help you. wish you a good health.