Cervical mucus is a fluid produced by glands in the cervix that plays an important role in fertility in women. The mucus contains electrolytes, proteins, and trace minerals like zinc. The exact makeup of cervical mucus changes throughout a woman’s cycle, altering its physical and chemical properties.
Most of the time, cervical mucus acts as a barrier to sperm, preventing them from entering the uterus. During ovulation, the mucus changes and becomes a perfect medium for sperm. Let’s explore what the cervical mucus is like under ideal conditions as well as ways it could present problems for fertility.
Appearance & Consistency of the Cervical Mucus
During much of a woman’s cycle, cervical mucus is thick and relatively dry. This state is linked to higher levels of progesterone, which is why women on birth control pills also have thicker cervical mucus. The thickness helps keep sperm from entering the uterus during non-fertile periods, and it also protects the uterus from bacteria and other microbes.
During ovulation, estrogen levels rise and production of cervical mucus increases, becoming thinner and wetter. When held between the fingers, the mucus is slippery and stretchy. At this stage, it is often compared to egg whites - you will often see people refer to “egg white cervical mucus” or EWCM when tracking their ovulation. This is the ideal consistency for cervical mucus when trying for a baby.
PH Levels of Cervical Mucus
The interior of the vagina is generally an unfriendly environment for sperm. If you remember high school chemistry, you know pH is a measure of how acidic or alkaline (or basic) a substance is. Numbers below 7 indicating an acid and numbers above 7 indicating an alkaline. Sperm perform best in a pH of 7.0 to 8.5 - neutral to slightly basic. However, normal pH for the vagina is between 3.5 and 4.0 - actually rather acidic.
Much as the consistency of cervical mucus changes during ovulation, its pH also increases, becoming more alkaline. When combined with semen following intercourse, the pH level can rise to 7.0 or higher for up to 48 hours. As we discussed in our post on the structure of the cervix , sperm can be held in cervical crypts for quite some time, being released slowly into the uterus. The increased pH makes the cervix a perfect environment for sperm to survive.
What is Hostile Cervical Mucus?
So, those are the qualities of ideal cervical mucus. But it’s also possible for the mucus to be in an undesirable condition, even during ovulation when you want it to do its best to transfer sperm. Problems with cervical mucus can vary, but in general, they are referred to as hostile cervical mucus, and often occur alongside other fertility problems. Hostile mucus may develop in several ways:
- Cervical mucus may be too acidic, so sperm cannot survive in it to reach the egg. This may be due to a bacterial or yeast infection.
- The mucus may be too thick, sticky, or dry - likely the result of hormone imbalance, a side-effect of medication, or age.
- Or, the mucus could contain inflammatory cells from an infection that prompt an immune response from the woman’s body. In this case, the immune system may also attack sperm trying to enter the uterus.
Treatment options for hostile cervical mucus include hormone treatments like synthetic estrogen, the mucus-thinning drug guaifenesin, or switching medications to ones that don’t interfere with the production of cervical mucus. In the case of inflammatory cells or acidic mucus, the underlying infection must be treated with antibiotics or other medication.
The condition of cervical mucus is important to fertility in women, and understanding the role mucus plays will help you make better health decisions when trying for a baby. If you want to learn more, check out these posts on tracking your fertility: