Hello linea nigra!

According to parenthub.com.au, Linea nigra is a condition in which pregnant women experience a darkening (hyperpigmentation) in the midline of the abdomen. It is typically a thin line of darker coloured skin that extends from the belly button downwards towards the pubic hair but may also extend upwards to just below the ribs. The line always runs vertically in the midline of the abdomen. The darkening is due to increased pigmentation of a ligament, the linea alba (white line) that exists in this area. When it becomes darkened, it is then referred to as the linea nigra (dark line).
Approximately 90% of pregnant women will experience some form of skin darkening (hyperpigmentation) during their pregnancy.
The exact cause is not known but it is thought to occur due to increased levels of hormones in pregnancy. These include:

• Melanocyte stimulating hormone – a hormone that stimulates melanocytes – the cells in the body that produce pigment and give rise to darker skin, freckles, birthmarks (naevi) etc.;
  
• Oestrogen; and
  
• Progesterone.
  

I know it's normal, but I'm glad it disappears after giving birth!!!