Early in pregnancy, the melanocyte stimulating hormone rises, which leads to increased melanin deposition. This affects approx. 70% of pregnant women and (1) usually occurs during the second and third trimesters (2) the pigmentation often gets darker with subsequent pregnancies
The hyperpigmentation is often is due to endocrinological changes (pregnancy hormones). This tends to consist of linea nigra (vertical line from the belly button down wards), darkening of the areola and melasma (on the face).
How to protect your skin and prevent worsening of hyperpigmentation
(1) Protect your skin from the sun. UV exposure can make skin discolorations darker. Hats and long sleeve clothing are recommended.
(2) For melasma on the face, apply sunscreen (SPF 50) daily during pregnancy, even when indoors. UV light still enters through the window and can affect your skin.
Hyperpigmentation after pregnancy usually disappears by itself, unless further triggered by UV damage or other factors. More resistant and longer lasting forms of post pregnancy hyperpigmentation can be treated effectively by The Hyperpigmentation Clinic peel treatment.