Hello, I just read your query. As you have mentioned about body stiffness of your baby and if it is frequent then the possible cause can be cerebral palsy which is most common cause behind this condition. * Other cause might be hypertonia where the rigidity is due to miscommunication between brain and nerves related to muscle. * Sometimes child is rigid without any cause. These all things can be differentiated only with clinical examination by a pediatrician. So do visit a nearby pediatrician to know the proper cause and get proper treatment accordingly. * I hope you find my answer helpful. Thank you.