White discharge before a period is normal and expected, and it can have a number of causes. Here are some key points from the search results:

• White discharge is called leukorrhea, and its filled with fluid and cells that are being shed from the vagina.
• The amount and consistency of discharge can change throughout the menstrual cycle due to hormonal fluctuations.
• Thick, white discharge is considered infertile and is most often seen between ovulation and the start of your period.
• White discharge before a period can also be a sign of usual reproductive system functioning, but it can have other triggers.
• White discharge can also be a sign of a yeast or other infection, particularly if it is lumpy or has a strong odor.
• If you notice any unusual changes in discharge, its important to consult a medical professional.

In summary, thick white discharge before a period is normal and expected, but its important to pay attention to any unusual changes in discharge and seek medical advice if necessary.