Why do i have a line in the middle of my stomach?

The line is called "linea nigra" and is a normal line of pigmentation that forms from the pubic area to your belly button (and sometimes higher). Some, but not all women get this during pregnancy and it is usually seen by darker skinned women. It is caused by elevations in estrogen, progesterone and alpha-melanocytic stimulation horomone- all horomones your body is producing in large quanties while you are pregnant. The line will go away towards the end of your third trimester or after you deliver. Hope that helps and good luck! Christine RN