- Melasma is common in pregnant women over 30 years old, in the last trimester, given birth; 32.8% had a history of melasma when pregnant; 27.3% used oral contraceptives; 37.9% had family history of melasma; 39.5% exposed to sunlight more than 1 hour a day; most of them have not worn face mask or worn face mask improperly; 77.3% havent had a habit of using sunsreens.