Lower back pain is not a sign of pregnancy. It is the result of added weight bearing during pregnancy causing overpronation that can lead to experiencing lower back pain. This is contrary to prior thought where low back pain during pregnancy was caused by Lordosis, or an over backward leaning of the body to balance the weight of the developing child. It’s possible for lower back pain to be a sign of pregnancy. Most commonly, lower back pain develops later in the pregnancy, starting at month five. However, the pain can begin earlier, as early as eight weeks.