The symptoms of lead poisoning include a wide range of physical and mental problems, including developmental delays, learning difficulties, irritability, lost appetite, unexplained weight loss, abdominal pain, vomiting, hearing loss and others. Babies exposed to lead may have slowed growth and delayed development. Adults can suffer severe headaches, vomiting, high blood pressure, abdominal pain, unexplained muscle and joint pain, mental decline, tingling, numbness or pain in extremities, mood disorders, abnormal sperm or reduced sperm count and constipation. Pregnant women may have miscarriages or premature births.