During pregnancy, many women notice a black or dark brown vertical line running down the middle of their stomach this is called the linea nigra, which means “black line” in Latin. It typically stretches from the belly button down to the pubic area, though in some cases, it may extend above the belly button as well. The appearance of the linea nigra is completely natural and is linked to the hormonal changes that occur during pregnancy.
The main reason this line appears is due to an increase in melanin production, which is triggered by higher levels of hormones like estrogen and progesterone.
These hormones stimulate melanocytes (the cells that produce pigment), causing certain areas of the skin to darken. This is also why pregnant women may notice darker nipples or patches of pigmentation on the face, known as melasma.
Though the linea nigra doesn’t serve a direct physical function for the baby, some cultures believe it helps midwives or mothers identify the baby’s position in the womb.
After childbirth, the line usually fades on its own as hormone levels return to normal. It’s a harmless, temporary part of the pregnancy journey that many women experience.