Causes and Treatment of Hostile Cervical Mucus

What Is Cervical Mucus Hostility? And What is the Role of Post-Coital Testing?

woman holding cough syrup on a spoon, taking it to improve hostile cervical mucus
Cough syrup is a popular over-the-counter remedy for hostile cervical mucus, but it isn't the best treatment option for everyone. Cervical fertility factors can be much more complicated. Jupiterimages / Photolibrary / Getty Images

Quick Definition: Hostile cervical mucus refers to cervical fluids (or cervical conditions) that are less than ideal for achieving pregnancy. Cervical mucus hostility may explain some cases of so-called unexplained infertility. However, more commonly, cervical factors occur alongside other causes of infertility.

In some cases, cervical mucus hostility is a side effect of medication. Clomid, for example, can cause hostile cervical mucus in higher doses.

Cervical mucus is essential to semen health and movement. Just before ovulation, cervical fluids increase and become more like raw egg white in consistency. This fertile quality cervical mucus nourishes sperm cells, helps them survive the vaginal canal, and enhances their movement through and up the cervical canal into the female reproductive system.

Problems with cervical mucus may make it more difficult to conceive. In rare cases, hostile cervical mucus alone can cause infertility.

It is estimated that between 3 and 8% of female infertility cases are caused by cervical mucus hostility. 

Among fertility specialists, there are differences of opinion on the best way to diagnosis and treat hostile cervical mucus. Diagnosis and treatment must take into consideration the full fertility picture, as well as the specific kind of hostile cervical mucus.

Post-coital (post-intercourse) testing was once a standard diagnosis tool for cervical mucus hostility.

Now, it is considered to be unnecessary and unhelpful. Still, some physicians continue to use the test in specific situations. (More on this below.)  

What May Cause Cervical Mucus to Be “Hostile”

Cervical mucus hostility is a general term that can refer to a number of possible problems with cervical fluids.

Some problems are more serious than others when it comes to fertility.

Thick, sticky, or dry cervical mucus: As mentioned above, just before ovulation cervical mucus should become more abundant and have the consistency of raw egg whites. Good fertile quality cervical mucus will stretch a couple of inches if you test it with your fingers.

Cervical mucus that never reaches this stage and remains thick, sticky, or clumpy may be considered hostile.

This may be caused by a hormonal imbalance (frequently along with ovulation problems), a side effect of medication, or age.

Acidic cervical mucus: Sperm cannot survive in an acidic environment. Cervical fluids that are too acidic may be considered hostile. This may be caused by a bacterial or yeast infection.

Presence of inflammatory cells: Another possible cause of hostile cervical mucus are inflammatory cells.

In this situation, there is a vaginal or cervical infection present. The woman’s immune system launches an attack on this infection, increasing the number of inflammatory cells present in the cervical mucus.

These immune cells may also attack sperm cells. (Innocent bystanders, in this case!) This, in turn, impacts fertility.

Anti-sperm antibodies: Sometimes, hostile cervical mucus refers to the presence of anti-sperm antibodies. In this situation, the cervical mucus itself may not appear any different to the naked eye than a person without the problem.

Anti-sperm antibodies are an immune response where white blood cells attack the sperm. Anti-sperm antibodies may be produced by the woman's body or may be present in the man's semen.

Treatment of Hostile Cervical Mucus

Treatment will really depend on the cause of the hostile cervical mucus and if there are other fertility factors.

In the case of less than fertile quality cervical mucus – assume there is no infection or anti-sperm antibodies – it may be possible to treat it using fertility friendly lubricants.

Or, if the lack of fertile quality mucus is a side effect of a medication, that medication may need to be discontinued to replaced with something else. (Never stop any medication without speaking to your doctor first.)

Another possible treatment for dry or sticky fertile mucus is with Ethinyl estradiol, a form of synthetic estrogen. When used in the short-term, it may improve production of cervical mucus and improve its fertile quality.

A popular over-the-counter treatment of poor cervical mucus quality is with guaifenesin, a medication most commonly found in cough syrups. It works by increasing and thinning mucus in the body.

If the cause of cervical mucus hostility is an infection, treating the infection with antibiotics or antifungals may be required.

If anti-sperm antibodies are present, IVF may be required. The research is unclear whether IUI significantly improves pregnancy rates in the cases of immunological fertility problems.

There’s some evidence that B-vitamins, especially folic acid and B-6 may help improve cervical fluid quality. The evidence isn’t very strong, though.

(Note however that folic acid is essential to fertility and healthy early pregnancy. Also, at least one study found that women who took a daily multivitamin were less likely to experience ovulatory infertility.)

There are a number of natural remedies proposed online, many with very little or no evidence to back them up.

Dietary suggestions include reducing dairy product consumption, decreasing carbohydrates, and changing the diet to be more alkaline (rather than acidic.) There’s no evidence for these suggestions.

Many websites suggest drinking more water to improve cervical mucus quality. If you are seriously dehydrated, it could affect your cervical fluids. But in most cases, drinking more water isn’t going to make a difference.

Post-Coital Testing for Hostile Cervical Mucus and Male Infertility

Post-coital testing used to be a routine part of a fertility work-up. Now, it is almost never used.

However, in cases of unexplained infertility, some doctors may perform this test.

If your doctor suggests post-coital testing, you will be asked to have sexual intercourse (at home) just before ovulation. This is when you should be most fertile and your cervical fluids should be most friendly to sperm.

Then, the next day or within 8 hours, you go to the fertility clinic. There, your doctor will take a sample of your cervical mucus.

The cervical mucus is examined microscopically for sperm cells. They will look to see if any sperm cells are alive and if they are moving normally.

The test is intended to diagnose hostile cervical mucus. However, it can be psychological upsetting for some couples. Its usefulness is highly debated. Also, the results can be difficult to interpret.

The test may be considered most helpful if...

  • a couple has been trying to conceive for less than 3 years
  • there are no clear female fertility problems
  • there are no clear male fertility problems, or the results of a semen analysis were borderline normal

In one study, couples with a positive post-coital test outcome were more likely to get pregnant within two years than those with a negative result. (About 68% of the couples conceived in the positive result group, compared to only 17% in the negative result group.)

The biggest benefit to post-coital testing is to decide whether to continue trying to conceive naturally or with IUI fertility treatment, or move to IVF treatment.

Those with a negative result on a post-coital test may benefit from IVF treatment.

More on cervical mucus:


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