Why has lower back pain persisted for a year after childbirth?

Patient's question:

Age
Detailed medical condition and purpose of consultation: I experienced frequent lower back pain during the 7th to 8th months of my pregnancy. If I sat for a long time, I couldn't straighten up my back. At night, when I woke up from sleep, my lower back felt like being pricked by needles, and my legs also felt numb, as if I could only slide forward by dragging something.
Current general condition: When I lie in bed and watch TV for a longer period, I find it difficult to straighten up my back, and it causes pain. First follow-up question: However, it has been almost a year since I gave birth, and the condition has not improved.

Doctor's answer:

Postpartum lower back pain is a relatively common phenomenon, and the causes include the following: Lack of activity after childbirth, combined with excessive dietary supplementation, leads to an increase in abdominal fat and body weight, placing greater strain on the lumbar muscles, resulting in muscle fatigue and lower back pain.
Poor posture. When caring for the baby and doing household chores, it’s important to frequently adjust your posture to avoid strain caused by prolonged static positions. Additionally, avoid excessive force to prevent uterine prolapse.