White discharge before a period is a common and natural part of the menstrual cycle. Hormonal fluctuations, especially changes in estrogen and progesterone levels, can cause vaginal discharge to become thicker and creamier in the days leading up to menstruation. In most cases, this discharge is healthy and helps keep the vagina clean and protected from infection. However, if the discharge is accompanied by a strong odor, itching, burning, or an unusual color, it may indicate an infection or another underlying condition. For complete information, refer to USA Fibroid Centers online.
https://www.usafibroidcenters.com/blog/what-does-discharge-look-like-before-your-period/