Library · Physiology
The mucus made by the cervix
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The cervix, the lower part of the uterus that connects it to the vagina, makes mucus that is not the same every day of the month. Its texture changes across the menstrual cycle.
What changes it is hormones. Before ovulation, which is when the ovary releases the egg, a hormone called estradiol rises. Estradiol makes the mucus more elastic and alters its proteins so that channels open up inside it. It is like a tight mesh that loosens and opens corridors: sperm pass through them more easily.
You can recognize this mucus just by looking, because it is clear, abundant and stretchy. That is why it is called egg white mucus. It shows up a few days before ovulation.
Once ovulation has passed, a different hormone takes over, progesterone, and it does the opposite: it thickens the mucus and takes away its stretch. The mesh closes again and passage becomes harder.
In brief
Cervical mucus, made in the cervix, changes texture across the menstrual cycle.
Before ovulation, estradiol changes its elasticity and opens channels that let sperm through more easily.
A mesh that opens into channels and then closes again.
This fertile mucus is clear, abundant and stretchy, like egg white, and appears a few days before ovulation.
Afterward progesterone thickens it and takes away the stretch, and passage becomes harder.
Sources (2)
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Menstrual Cycle, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingNatural Family Planning, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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