I have a very clear odourless jelly- like vaginal discharge. What causes this?

Cervical mucous. Cervical mucous secretion is the most common cause of clear odorless discharge. This tends to increase midcycle and is an indicator of ovulation. Some women produce more than others. There are rare conditions that may also cause an increase in production so be sure to see your gynecologist regularly.
Vaginal discharge. Vaginal discharge is common, and normal discharge occurs 30% of the time. There are other causes of vaginal discharge including fungal infections, bacterial vaginosis (overgrowth of normal bacteria), as well as sexually transmitted diseases. If you're having symptoms, you should see your family practice physician.