An American survey has shown that only a few women know much about the female cycle.
We shed some light on the matter:
What you will find on this page:
- How does a woman's cycle work?
- 1st half of the cycle: desquamation and follicular phase before ovulation
- Middle of the cycle: ovulation and the fertile cycle phase
- 2nd half of the cycle: luteal phase after the day of ovulation
- How can I calculate and monitor my cycle?
- What role do hormones play in the menstrual cycle?
- What other women want to know about the female cycle:
How does a woman's cycle work?
The female cycle begins with the first menstruation in puberty and ends with menopause. The most common cycle length is 27 cycle days.
Various cycle disorders, such as an irregular period, can affect the cycle and menstruation length as well as the intensity of the period. There are also some functional disorders or diseases, such as endometriosis, PCOS or corpus luteum insufficiency, which can impair the 'normal' course of the menstrual cycle.
The phases of the female cycle
As our chart shows, the menstrual cycle is divided into two halves. In between lies the fertile cycle phase, in which ovulation takes place. With a cycle length of 27 cycle days, the female cycle proceeds as follows:
1st half of the cycle: desquamation and follicular phase before ovulation
In the first half of the cycle, the old uterine lining and the corpus luteum are expelled with the period. After menstruation ends, new uterine lining is built up while the egg follicles mature in parallel.
Desquamation phase: shedding of the uterine lining
Hormone withdrawal causes the regression of the uterine lining and the shedding of its upper layer.
Follicular phase: follicle maturation & build-up of the lining
During the follicular phase, the female body prepares for the fertilisation of mature eggs. During this phase, several egg follicles are formed. Each follicle contains a single, still undeveloped egg. These eggs develop in the ovary under the influence of the hormone FSH (follicle-stimulating hormone). The hormone oestrogen is produced in the walls of these follicles.
In the first days of the follicular phase, the oestrogen level is still low. Under the influence of FSH, the follicles in the ovaries grow larger and larger, which in turn causes the oestrogen level to rise steadily in the days before ovulation. This rise causes the uterine lining, which was shed during the last period, to be rebuilt (= proliferation phase).
Hormone levels in the 1st half of the cycle
At the same time, the quality of the cervical mucusimproves in the 1st half of the cycle. Sperm can now 'travel' particularly well. The probability of getting pregnant is highest during the time shortly before ovulation up to the day of ovulation.
Middle of the cycle: ovulation and the fertile cycle phase
During ovulation, the follicles grow larger as ovulation approaches, and the oestrogen level rises, which in turn signals the pituitary gland to release more LH (luteinising hormone).
Hormone levels during ovulation
Timing of ovulation in the menstrual cycle
The elevated LH level causes the most developed follicle to burst and release its now mature egg into the ovary. Ovulation has thus taken place and the egg remains fertilisable for a short time.
Not to be confused: the time during which the egg can be fertilised does not correspond to your fertile days. An egg can be fertilised for up to 24 hours. How long do sperm survive? Up to 5 days. This results in a period of 6 days during which you are fertile.
Various ovulation symptoms help you determine the day of ovulation.
Female cycle: are several ovulations possible?
In general, only one of the eggs is released. However, fraternal twins are proof that several ovulations are possible in menstrual cycles. But note: if several ovulations occur, they happen within a few hours of each other. A second ovulation at a greater interval from the first is not possible, as the rising progesterone in the blood prevents further ovulations. In some cycles, especially after hormones have been given to support egg maturation, 2-3 follicles can sometimes form. For several ovulations in one cycle, however, the follicles must all be roughly the same size and maturity.
2nd half of the cycle: luteal phase after the day of ovulation
With the bursting of the follicle, your basal body temperature rises by a few tenths of a degree in the luteal phase and remains elevated until the next period. After the plateau phase is reached, you are infertile until the end of your menstrual cycle.
After ovulation, the follicle is transformed in the luteal phase into a gland that is called corpus luteum ('yellow body') because of its colour (yellow colour: fat deposits). The corpus luteum now produces the hormone progesterone. The increased hormone level prepares the uterine lining for the implantation of the fertilised egg (blastocyst). It also causes the cervical mucus to become viscous and less permeable again, reducing the lifespan of sperm.
Hormone levels in the 2nd half of the cycle
After that, there are two options, depending on whether you have become pregnant or not.
Preparation for the period
Option A: if the egg was not fertilised, there is no pregnancy. The corpus luteum dies about 12 to 16 days after ovulation and the oestrogen and progesterone levels drop. As a result, the uterine lining is shed, which can cause period pain in many women. The basal body temperature drops and your period begins. With the onset of the monthly period, a new menstrual cycle begins.
Hormone levels at the end of the cycle
Female cycle after fertilisation of the egg
Option B: if the egg was fertilised, it travels from the ovary to the uterus, which takes a few days. Once it has arrived there, the uterine lining is already prepared for implantation through the effect of oestrogen. If the fertilised egg was able to implant, the corpus luteum remains and begins to produce large amounts of progesterone. As a result, the uterine lining is not shed and the period does not start.
The basal body temperature remains at an elevated level and the hormone hCG (human chorionic gonadotropin) is produced. These pregnancy signs are among the reliable symptoms that indicate fertilisation.
Cycle course during pregnancy
How can I calculate and monitor my cycle?
First of all, it is important to know that no two cycles are the same! It can differ from woman to woman and from month to month.
To gain a first awareness of the cycle length and its regularity, many women keep a period calendar. It can give you first important clues about what is happening in your cycle.
Other women often make do with simple ovulation calculators. However, these only help to a limited extent in calculating your menstrual cycle, as they assume average cycles.
If you want to calculate your cycle, you should do so with the help of reliable ovulation symptoms such as the basal body temperature and/or the consistency of your cervical mucus.
The cyclotest mySense app or the cycle computer cyclotest myWay can observe these symptoms and clearly analyse your individual cycle. Both tools are medical devices and are connected to a thermometer. Both also have an integrated cycle calendar. The fertile days are calculated individually and reliably, and additional symptoms such as mood or libido can also be documented.
What role do hormones play in the menstrual cycle?
A woman's menstrual cycle is controlled by higher centres in the brain, with the two hormones FSH (follicle-stimulating hormone) and LH (luteinising hormone) playing a particularly important role. The pituitary gland releases FSH and LH into the blood, stimulated by the production of GnRH (gonadotropin-releasing hormone) by the hypothalamus in the brain.
During the menstrual cycle, the amounts of hormones in your body change. This cycle can affect the following:
- your mood
- your libido
- your athletic performance and
- your skin
Click through our image carousel to find out how to make the most of your cycle. See how your mood, your libido, your athletic performance and your skin change during the different cycle phases:
Making the most of the cycle phases
Changes can also show in how you perceive your breasts. This is because the breasts react very sensitively to hormonal changes in a woman's cycle. By the way, the last day of your period is also the best day to examine your breasts.
Keep reading? You might like this:
Hormone-free contraception
Hormone-free contraception covers all contraceptive methods and contraceptives that work without hormones. They can be divided into four groups.
In our article, we explain everything about contraceptive reliability as well as the advantages and disadvantages of the individual contraceptive methods.
Can I get pregnant after stopping the pill?
Do you want to get pregnant after stopping the pill? Do you want to stop taking the contraceptive pill to have a baby? Or have you already stopped taking the pill and are now wondering whether there is anything else to consider in fulfilling your wish to have a child? We have compiled in our article whether a hormonal contraceptive influences your chances of fertility and what else you should know.
Basal body temperature
The basal body temperature is measured in the morning after waking up. That is why this body temperature is also called waking temperature. At night, the body temperature drops to its lowest value; during the day, it rises slowly and reaches its maximum in the afternoon. Over the course of the cycle, the temperature level typically changes, which allows conclusions about ovulation and thus the fertile & infertile days.
What other women want to know about the female cycle:
Sources:
- 1 Lundsberg, L. S. et al.: Knowledge, attitudes, and practices regarding conception and fertility: a population-based survey among reproductive-age United States women. Fertility and Sterility, Vol. 101. 2014.
- 2 Malteser Arbeitsgruppe Natürliche Familienplanung (Hrsg.): Natürlich und sicher. Das Praxisbuch. 18. Auflage. Stuttgart 2011.
- 3 Raith-Paula, E. et al.: Natürliche Familienplanung heute. Modernes Zykluswissen für Beratung und Anwendung. 5. Auflage. Heidelberg 2013.
- 4 Weschler, T. (2016). Familienplanung: Das Standardwerk zur natürlichen Empfängnisverhütung, Kontrolle der Fruchtbarkeit sowie Erfüllung des Kinderwunsches. Deutschland: mvg Verlag.