What is the linea nigra?

The linea nigra is very common in pregnancy and usually affects darker women more than fair woman.   The linea nigra usually appears during the second trimester and should disappear after delivery, although this sometimes takes a few months. In some cases the colour fades but the line doesn’t disappear completely. It runs either from just below the rib cage or from the belly button all the way down to the pubis. It is caused by pregnancy hormones that increase production of the pigment melanin, a process which is known as hyper-pigmentation, but why this occurs in a straight line down the belly is not known.  The skin of you nipples, abdomen and genital region might also become darker and may or may not fade back to their original colour, even after your baby is born. Folic acidis said to help reduce discolouration.