"Egg white cervical mucus, abbreviated by EWCM on fertility charts and in fertility forums, is a phrase used to describe the most fertile kind of cervical mucus. Cervical mucus of this type looks a lot like raw egg whites, and you may notice it just for one or two days before you ovulate. It's also possible to have egg white cervical mucus for up to five days before ovulation or for just one day, though two or three days is more common."