Because its volume and consistency vary during the cycle, the observation of cervical mucus is one of the natural methods to determine the date of ovulation, and therefore to optimize the chances of pregnancy … or on the contrary to avoid to get pregnant.

It is a white, viscous substance secreted by the endocervical glands of the cervix. Composed of mucus, water, nutrients and enzymatic substances, cervical mucus forms a network of three-dimensional meshes which, over the course of the cycle, will more or less tighten, preventing or promoting the passage of spermatozoa. Therefore, it plays an essential role in fertility. During fertile days, it promotes the passage of spermatozoa to the cervix, and protects them from the acidity of the vagina; in infertile period, it forms a plug in the neck which obstructs it.

When it flows into the vagina, cervical mucus is the cause of vaginal discharge, called “white discharge” that all women observe regularly.

The amount, composition and consistency of cervical mucus changes over the course of the menstrual cycle:

• at the start of the cycle, during the follicular phase, cervical mucus is very scarce, white and thick. Its role: to hermetically seal the cervix to protect it from bacteria and prevent the passage of sperm;
• as ovulation approaches (within 48-72 hours) cervical mucus increases in quantity and becomes more fluid and stringy.
• on the day of ovulation, its texture is comparable to that of egg white: fluid, elastic, shiny and transparent, it is also more abundant. Its meshes have widened in order to let sperm pass through, while filtering out poorly formed or poorly vigorous sperm. At the same time, her PH has increased (between 7 and 8) to compensate for the acidity of the vagina and promote sperm survival;
• after ovulation (luteal phase), the mucus becomes impoverished and dries up. It will resume its role of closing the cervix.

Observing his cervical mucus helps determine his ovulation period and therefore his fertile period. You just need to take a little cervical mucus with your two fingers and appreciate the texture. The objective: to detect when the cervical mucus is more abundant, a sign that ovulation is approaching, and the texture of “egg white” (the mucus stretches a few centimeters between the two fingers), which signs the ‘ovulation. It is during key days that you will have to have sex to increase your chances of conception.

Is this method effective? Yes, as long as you have a good knowledge of your body and observe it well. In addition, many elements can modify the cervical mucus: sexual desire (we can then confuse lubrication and cervical mucus), semen, a vaginal infection.

Observing your cervical mucus to know its fertile period can also be used, on the contrary, as a method of contraception. The Billings method or Billings ovulation method (BOM), named after two Australian doctors, thus consists of practicing abstinence (no sexual intercourse, even with a condom or interrupted coitus) :

• the days during which cervical mucus is present as well as the following three days;
• during menstruation;
• on days when bleeding, even light, occurs during the cycle, and the next three days.

However, this method of contraception is not 100% effective. According to the WHO, the Pearl Index (index to assess the reliability of a contraceptive method) of the Billings method is 3% (3 out of 100 women using this method became pregnant within a year) (1 ).