The back pain of sleeping after giving birth to 3 babies may be related to factors such as being cold and tired, poor breastfeeding posture and lumbar muscle strain. 1. Cold and tired: pregnant women after giving birth to three babies body is very weak, weak resistance, if not timely warmth, easy to appear after cold or tired, back pain. 2. Improper breastfeeding posture: If the pregnant woman after giving birth to three babies, usually often breastfeeding or holding a child, and improper posture, it is easy to appear back pain. 3. Lumbar muscle strain: the pregnant woman herself is pregnant when the waist and back muscle load is larger, if the birth of three babies when the production force is too large easily lead to the waist and back muscle strain, back pain. In addition, there may be other reasons for back pain after having 3 babies, it is recommended to consult a doctor in time to clarify the specific causes and give targeted treatment.