The stretching and distension of the bump causes the skin to have micro-tears which are are known as striae gravidarum (SG).
SG are purplish wavy lines on the bump, breasts and thighs. These are battle scars of your pregnancy. The good thing is that they lightens after delivery but the bad thing is that striae may be permanent.
Striae are preventable
There is a strong genetic cause of striae. So, ask your mom. If she had striae when she delivered you, you are more prone to have SG. To prevent tummy stretching, strengthen your abdominal muscles. Strengthening your abs reduces the tear on the connective tissue and also protects your core muscles and back.
Use stretch mark cream to prevent SG. The silicon-based cream reduces SG by 50-70%. Try special maternity panties and bump support girdle. The tears would be minimised as tummy is more supported. Unfortunately, seaweed wraps and massages have not shown to help.