The causes of baby toenails turning upward include: heredity, lack of trace elements, trauma, fungal infection and so on. 1. Heredity: It is usually a congenital deformity caused by abnormal anatomical structure. If the parents’ toenails also turn upwards, it is usually hereditary. 2. Lack of micronutrients: When babies lack micronutrients, especially iron, it is easy for them to develop spatulate nails, resulting in upturned toenails. It is recommended to take reasonable supplements for the deficient elements under the guidance of the doctor. 3. Trauma: If the toenail is squeezed by external force, it will also lead to upward turning. You should consult a doctor in time and recover in a short period of time with proper treatment. 4. Fungal infection: If the baby’s toenail is infected by fungus and caused by onychomycosis, it will also cause the toenail to turn outward, and there will also be a change in the color of the toenail as well as the toenail becomes brittle and other symptoms. As you can see, baby toenail upturning should be taken seriously, and it is recommended to go to the hospital in time.