During your second trimester of pregnancy, you will notice some skin changes, usually pigmentation and discoloration in certain areas. One of the most remarkable is the formation of a dark line that runs from your belly button down to your pubic area. This stripe is called linea nigra (or linea negra, which translates to "black line"). As with other skin pigmentations you may have (usually darker areolas and patches on the face and neck), these skin anomalies are caused by pregnancy hormones.

Some say that preventing sun exposure and sufficient folic acid in the diet can make the line less noticeable. But apart from the appearance, there really is nothing to worry; it's harmless and will fade away on its own within a few weeks after you give birth!