Dermatographic urticaria is a skin disorder and one of the most common types of urticaria, affecting 2–5% of the population. Signs and symptoms
The condition manifests as an allergic-like reaction, causing a warm red wheal to appear on the skin. As it is often the result of scratches, involving contact with other materials, it can be confused with an allergic reaction, when in fact it is the act of being scratched that causes a wheal to appear. These wheals are a subset of urticaria (hives), and appear within minutes, in some cases accompanied by itching. The first outbreak of urticaria can lead to other reactions on body parts not directly stimulated, scraped, or scratched. In a normal case, the swelling will decrease without treatment within 15–30 minutes, but, in extreme cases, itchy red welts may last anywhere from a few hours to days. Causes
Symptoms are thought to be the result of histamine being released by mast cells on the surface of the skin. Despite the lack of antigens, histamine causes the skin to swell in affected areas. If the membrane that surrounds the mast cells is too weak it will easily and rapidly break down under physical pressure, which then causes an allergic-like reaction.Symptoms can be caused or induced by:

The underlying cause of dermographism is not known, and it can last for many years without relief. The condition may subside and be effectively cured; however, it is often a lifelong ailment.
A highly durable network of ligaments surrounds these joints giving them tremendous strength. The pubic symphysis has a  fibrocartilage joint which may contain a fluid filled cavity and is avascular; it is supported by the superior and arcuate ligaments. The sacroiliac joints are synovial, but their movement is restricted throughout life and they are progressively obliterated by adhesions. The nature of the bony pelvic ring with its three joints determines that no one joint can move independently of the other two. Relaxin hormone
Relaxin is a hormone produced mainly by the corpus luteum of the ovary and breast, in both pregnant and non-pregnant females. During pregnancy it is also produced by the placenta, chorion, and decidua. The body produces relaxin during menstruation that rises to a peak within approximately 14 days of ovulation and then declines. In pregnant cycles, rather than subsiding, relaxin secretion continues to rise during the first trimester and then again in the final weeks. During pregnancy relaxin has a diverse range of effects, including the production and remodelling of collagen thus increasing the elasticity of muscles, tendons, ligaments and tissues of the birth canal in view of delivery. Although relaxins main cellular action in pregnancy is to remodel collagen by biosynthesis (thus facilitating the changes of connective tissue) it does not seem to generate musculoskeletal problems. European Research has determined that relaxin levels are not a predictor of PGP during pregnancy. Gait changes
The pregnant woman has a different pattern of "gait".