We often hear about “egg-white mucus” for identifying the fertile phase and ovulation. Peak-type cervical mucus often does look like egg-white, BUT not always.
All cervical mucus is fertile. If you see cervical mucus, you know that your “gate” is open, an egg is developing, and your body is preparing to ovulate. You might see something pasty and white, or smooth and creamy, or like egg-white, or simply feel a slippery, lubricative sensation when youwipe yourself but not see any substantial mucus at all. All of these would identify a fertile day.
The differences between them are important to note only because you want to decide whether you’re seeing “non-peak” or “peak-type” mucus, so you can do things like identify Peak Day, know when to do a Count of 3, and assess reproductive health.
(Of course, if you have some discharge every day of your cycle, you’ll want to routinely use the “Essential Sameness Question” and identify your Basic Infertile Pattern. For more on that, see this post.)