Linea nigra: Learn when linea nigra

Learn when linea nigra, or the pregnancy line, appears, what causes it, and when you can expect it to go away. Linea nigra is caused by hyperpigmentation that often occurs during pregnancy. Learn what causes it, what to expect, and more. Linea nigra usually extends from the symphysis pubis (the cartilaginous joint between the pubic bones) to the umbilicus (the belly button), but it can extend further up to the xiphoid process (the lowest point on the sternum) [4,6,10]. The linea nigra is a dark line that can show up on your belly during pregnancy – it's super common and totally normal. It's caused by pregnancy hormones triggering more melanin production in your skin, but why it shows up where it does is still a bit of a mystery.