The Cervical Mucus Method Can Be Effective But Has Its Drawbacks

Considered a natural birth control method, the cervical mucus method is a low-cost way of monitoring the days you ovulate by self-tracking daily cervical mucus secretions. This fertility-awareness-based method helps you determine which days you are fertile, and consequently, know when the best time is to have unprotected sex to prevent pregnancy.

"Cervical mucus is a fluid secreted by glands located around the cervix. The consistency and amount of this mucus changes along with hormonal changes throughout the reproductive cycle," said Jessica Shepherd, M.D., an OB-GYN, chief medical officer of Verywell Health.

The changes in appearance, texture and odor of the mucus can help determine when a woman is about to ovulate, allowing her to make better-informed decisions as to whether or not to have unprotected vaginal sex.

"A vaginal discharge resembling raw egg whites signals that you're most likely ovulating and is the best time to have sex to get pregnant," Shepherd said. If your discharge is sticky or nearly nonexistent, you're likely not ovulating.

The day of ovulation—referred to as "Peak Day"—defines the last day that women can observe the cervical mucus present. Some period tracking or health monitoring apps actually have a widget that makes this easier.

While many women practice the cervical mucus method alone, it can be paired with a fertility-awareness method to ensure its efficacy. Most of the time, this would involve checking one's basal body temperature (BBT). In tandem, these are referred to as the sympto-thermal or sympto-hormonal method.

Is the cervical mucus method effective?

Observational and clinical studies have suggested cervical mucus monitoring (CMM) is an uncomplicated and effective approach to preventing pregnancy.

A 12-month prospective clinical efficacy study on the effectiveness of CMM suggests correct use of the method led to an unintended pregnancy rate of just 2.1 percent for the first year of use. This indicates a 97.9 percent effectiveness in avoiding pregnancy. If not followed correctly, the method's effectiveness in avoiding pregnancy would lower to 85.8 percent.

Hence, based on this study, the method's effectiveness is between 86 percent and 98 percent.

Furthermore, a 2015 study published in Fertility & Sterility indicated that cervical mucus patterns reflect rising estradiol (the form of estrogen mainly made in the ovaries). When done correctly, self-identification of peak mucus can be an accurate marker of the onset of the fertile and infertile ­phases of the menstrual cycle.

Disadvantages of the cervical mucus method

While the research is promising, there are some disadvantages to the cervical mucus method, according to Alyssa Dweck, M.D., F.A.C.O.G., who specializes in female sexual and reproductive health. Since the success of the method is hinged on behavior, correct use and motivation are crucial to its effectiveness.

"Even with a tracking app, many women might find it hard to update their charts on a regular basis. Many women are not given a proper briefing with regard to how to do a daily mucus check or even what symptoms to look out for," Dweck said. "Moreover, interpretation of results tends to call for additional advice and/or assistance from a qualified medical professional."

Other factors may affect a woman's menstrual cycle, such as stress or a sudden illness, and these may throw the fertile window off by as little as two days or up to a month, diminishing the effectiveness of the method. Additionally, the cervical mucus method does not protect you from sexually transmitted infections (STIs).

Hormonal factors may also affect the production of mucosal secretions in a woman's body. Therefore, perimenopause, breastfeeding or polycystic ovary syndrome (PCOS) can affect one's discharge, as will a number of STIs. Chemical factors and personal hygiene habits may also come into play when it comes to altering the texture and composition of one's secretions.

So, while some research has found the cervical mucus method to be effective, there are many factors that can influence the efficacy.

What are the steps involved in observing cervical mucus?

Dweck explained there are three ways by which the cervical mucus method may be done and all three involve powers of observation:

1. Prior to urinating, wipe the opening of the vagina with white toilet paper or facial tissue. Check the color and texture of the mucus that comes away with the tissue.
2. Observe the color and texture of the discharge on your underwear.
3. Insert clean fingers (the index and middle) into the vagina up to the second knuckle, then pull out to check the color and texture of the mucus on your fingers.

Interpreting your cervical mucus findings

You need to record your findings in a chart. Use the following abbreviations for guidance:

• S: sticky
• W: wet
• C: creamy
• EWCM: egg white

After marking down your findings, you can proceed to interpret them.

If your mucus feels sticky, chances are you're not yet ovulating. If your mucus is wet, then you're also likely not ovulating yet. If what you find is creamy, you're getting close to your day of ovulation. And if you marked your finding as egg white, then you are ovulating and it's the best day to get pregnant (or avoid sex).

Who might benefit from this method of birth control?

The cervical mucus method is recommended for women in their 20s and 30s whose cycles are regular. Due to hormonal fluctuations, it isn't recommended for women who are in their early to mid-40s, as they may already be in the throes of perimenopause.

"Women who want to use other ways to help track their best windows of fertility can use cervical mucus secretions in order to prevent pregnancy," Dweck said. "Due to studies demonstrating that observing the cervical mucus can identify the days with the highest pregnancy probability, it can be a very useful ­approach for women for birth control."

Likewise, Dweck added that since it is a natural mode of contraception, the cervical mucus method is recommended for those who, for reasons of religion, shun artificial or barrier-driven methods, such as chemical birth control, condoms and intrauterine devices.

The cervical mucus method is an inexpensive yet effective family-planning method. However, "this is not a foolproof method of birth control," Shepherd warned. "If you're trying to avoid getting pregnant, other methods should be used in conjunction, such as condoms, birth control pills or IUDs."

In any case, your choice of birth control is a matter best discussed with your gynecologist, who can gauge your situation and lifestyle to choose an appropriate and effective mode of contraception.