Sudden convulsions when babies are breastfeeding may be caused by vitamin D deficiency, febrile convulsions, epilepsy and other reasons. 1. Vitamin D deficiency: Vitamin D is an essential nutrient for the human body, which promotes the body’s absorption of calcium, and calcium deficiency can lead to muscle twitching. Seizures can be as short as a few seconds or as long as several minutes, and infants usually do not have a fever. 2. Febrile convulsions: If the infant has fever itself, due to the fact that the development of the brain’s nervous system is not very perfect, it will cause abnormal discharges of nerve cells during the fever, triggering the occurrence of convulsions. 3. Epilepsy: Babies may have epilepsy and have convulsions while breastfeeding. Epileptic convulsions are usually caused by abnormal discharges of the brain nerves, and generally show symptoms such as rolling eyes and loss of consciousness. There may be other reasons why a baby suddenly convulses while breastfeeding, so it is recommended to go to the hospital in time, complete the examination to clarify the cause of the disease, and then give targeted treatment or therapy under the guidance of the doctor.