Cervix: Hints Of Anatomy
- The cervix (also called neck or cervix ) is the lowest and narrowest portion of the uterus , a hollow, pear-shaped organ located in the female pelvis , between the bladder (anteriorly) and the rectum (posteriorly).
- The cervix is in direct connection with the vagina and, on gynecological inspection, is visible as a cylindrical formation with an orifice in the center . The latter represents the end of the cervical canal, which connects the uterine cavity to the vagina.
- The cells lining the cervix are not all the same: the ectocervix (also called the exocervix) is lined with squamous cells (like the vagina), while the endocervix (closer to the body of the uterus) has a columnar epithelium glandular type. The transition zone between these two cell types is called the squamous columnar junction .
What Is Cervical Mucus Used For?
Cervical mucus performs several important functions:
- Lubricates the neck of the uterus (or cervix)
- It helps to protect the internal genital organs, such as the body of the uterus and fallopian tubes, from infection : cervical mucus has bacteriostatic properties
- It opposes the passage of sperm in the phases in which the woman’s body is not prepared for fertilization
- Facilitates the passage, survival and capacitation of sperm (the process by which they acquire fertilizing capacity ) during the ovulatory phase , a period in which female fertility is at its maximum; also in this phase the cervical mucus helps to trap the less vital spermatozoa, not completely mature or with unfavorable morphological characteristics
- During pregnancy, cervical mucus becomes particularly thick and accumulates in the cervical canal, blocking it and creating a protective barrier for the fetus called a mucus plug . This plug is lost shortly before delivery .
All these functions of the cervical mucus depend on the woman’s endocrine balance , i.e. on her hormone levels. In particular:
- Estrogens , whose peak occurs around ovulation , stimulate the cervical cells to secrete a viscous, transparent and acellular mucus, which favors the survival and migration of the sperms . In addition to becoming more lax, clear and abundant, similar to egg albumen , in the ovulatory phase the cervical mucus becomes more alkaline, in order to neutralize the typical acidity of the vaginal canal and increase the survival of the spermatozoa.
- The lack of estrogen and progesterone , whose peak occurs after ovulation , stimulate the secretion of a thicker and more acidic cervical mucus, which opposes the passage of sperm → a sort of plug is created which blocks the external uterine orifice, through which the cervix opens into the vagina.
How Is Cervical Mucus Produced?
Cervical mucus is essentially the secretion product of the endocervical cells, to which small quantities of fluids from the endometrium and fallopian tubes are added.
Components Of The Cervical Mucus
- Water : main constituent, it alone represents 90% of cervical mucus → it increases in percentage terms in the pre-ovulatory phase (up to 95-98%) and decreases in the other phases of the cycle → this change plays an important role in some contraceptive methods based on observation of cervical mucus
- Glucose and other organic components such as glycerol , the concentration of which increases during sexual excitement and which probably facilitates fertilization → the availability of glucose also increases the vitality of spermatozoa, which have limited energy reserves
- Soluble amino acids and proteins
- Electrolytes ( calcium , sodium and potassium , zinc , copper , iron , manganese and selenium ) → increase in the days immediately before and after ovulation
The mucus may contain specific antibodies , capable of immobilizing and neutralizing the partner’s sperms → immunological incompatibility → difficulty for the couple to have children.
Cervical Mucus: Quantity
The quantity of cervical mucus produced at the beginning of the menstrual cycle has been quantified as 20 mcg/day, while in full ovulation this quantity can rise up to 600-700 mcg/day; however, the phenomenon is subject to wide individual variability.
When It Changes Appearance
Cervical Mucus: What Can Cause Changes?
Several factors can cause the cervical mucus to change. Some of these include:
- Menstrual cycle : As mentioned, cervical mucus can change during each phase of the cycle. Immediately before and during ovulation, mucus is usually clear, stretchy, and sticky (reminiscent of raw egg whites). After ovulation, it thins out and becomes thicker and stickier. During your menstrual cycle, you may also experience a few days with very little or no mucus.
- Some contraceptive methods : Hormonal contraceptive methods typically thicken cervical mucus to make it difficult for sperm to enter the uterus and fertilize an egg .
- Infections : Bacterial , yeast , and sexually transmitted infections can cause mucus to change color or smell.
- Other Factors : Certain medications, feminine hygiene products, douches , pregnancy, breastfeeding , sexual intercourse can affect the appearance of cervical mucus.
- Yellowish and creamy discharge (probable cause: gonococcal infection);
- Green-yellow foamy vaginal discharge associated with itching and irritation (probable cause: Trichomonas );
- White, grayish, foamy, fetid-smelling discharge especially after sexual intercourse or intimate hygiene (probable causes: bacterial vaginosis , Gardnerella vaginalis );
- Modest vaginal discharge adhering well to the walls, associated with intense itching and burning , white and with a caseous consistency (probable cause: candidiasis );
- Mucopurulent vaginal discharge associated with pain during sexual intercourse (probable cause: Chlamydia , Ureaplasma urealyticum ).
Medications And Treatments That Alter Cervical Mucus
- Contraceptive pills – in addition to preventing ovulation – increase the density and acidity of the cervical mucus, hindering the passage of sperm
- Estrogens administered alone, in the absence of progestogens, instead increase the “fertility” of the cervical mucus
Fertility And Contraception
Observing the changes in the cervical mucus during the menstrual cycle it is possible to obtain indications on which are the fertile days of the woman (days in which she has the possibility of becoming pregnant). This makes it possible to plan sexual intercourse in order to reduce or increase – depending on the case – the chances of pregnancy.
For this reason, the observation of cervical mucus is one of the strategies adopted by various methods of natural contraception , such as the Billings method and the symptothermal method.
Fertile Period And Observation Of The Cervical Mucus
We have seen how in the ovulatory period – which coincides with the moment of maximum fertility of the woman (fertile window) – the cervical mucus becomes clearer, stringy and abundant. These characteristics can be appreciated with the naked eye, but also with the aid of laboratory techniques.
In addition to being particularly elastic and stringy, the cervical mucus secreted during ovulation, if left to dry on the slide and observed under the microscope, has a characteristic fern-like arborization; this peculiarity is known as ferning .
The term ” spinnbarkeitt ” or filanza refers instead to the elasticity of the mucus: if it is placed between two slides and removed from them, it forms filaments up to 8-12 centimeters long.
Observing the changes in the cervical mucus during the menstrual cycle it is possible to obtain indications on which are the fertile days of the woman.
Natural contraceptive method based on the recognition of ovulation by carefully observing and studying the characteristics of the cervical mucus. When the mucus is particularly stringy, transparent and abundant, causing a “wet” sensation, the woman is most likely in the ovulatory phase. Therefore, when the woman recognizes this particular signal sent by the body, the couple should abstain from intercourse to avoid an unwanted pregnancy, at least until the third day after the peak of mucous secretion.
Symptothermal Contraceptive Method
It is based on the joint evaluation of cervical mucus and basal temperature: the woman should abstain from intercourse three days before and three days after the maximum body temperature peak , during which the cervical mucus is particularly stringy and thick.