Fertility signs in cycle’s phases

Each menstrual cycle can be divided into 2 phases:

  • follicles phase - connected with maturation of follicles;
  • corpus luteum phase – starting from ovulation (release of mature follicle) till the end of the cycle.

Follicle phase known also as pre-ovulatory phase can have different length. The length differs between women and it changes with age. Differences between your cycles are also possible mainly due to the change of climate, stress, illness, lack of sleep, crash diet; then your ovulation may be postponed and the pre-ovulatory phase lasts longer.

The estrogen has the dominant role in this phase. It causes the given changes within the woman’s reproductive organs.

Under the influence of estrogens mucous membranes start growing. The cervix opens, gets softer and moves to high position at the same time secreting the cervical fluid.

The estrogen released by the developing follicles, and later by the dominant follicle, causes the lining of the uterus, the endometrium, to grow and thicken in preparation of implantation of a fertilized egg.

From the view point of couple’s fertility we can observe 2 stages :

  • relatively infertile phase;
  • combined fertile phase;

Relatively infertile phase starts at the beginning of the cycle (i.e. from the first day of menstrual period) and usually has different length. During that phase the cervix is closed, hard and low situated. The cervical fluid isn’t produced.
The environment in the vaginal tract is acidic so that it is a protection against pathogenic bacteria, viruses and mycotic fungus. It is also hostile environment for sperm, as the sperm cells need alkaline solution to survive. It means that after intercourse the sperms cells die in a few hours.

With the rise of the estrogen level the fertile phase begins. The egg matures in the ovary, the cervix starts opening, it moves up and softens. The appearing cervical fluid changes the vagina’s environment to an alkaline solution that enables the sperm cells to survive and get into the women’s genital tract.

At the beginning the cervical fluid is thick, white and non-transparent but with the estrogen rise it becomes transparent, tensile and smooth.

Thick cervical fluid is a kind of net which is hard to go through and sperm cells are being selected – the damaged and poor developed are kept away. The more watery and tensile the cervical fluid is the more sperm cells can go through it. The more fertile characteristic the cervical fluid is the better environment for sperm it becomes. As it is nutritious and enables the greater mobility.


The corpus luteum phase starts from the ovulation when the mature follicle is released and changes into corpus luteum secreting mainly progesterone. The main characteristic feature of corpus luteum is its length – around 10 to 16 days – distinct among different women but almost the same when one woman is taken into consideration.

After ovulation, progesterone, produced by the corpus luteum, is present in higher amounts. Under its influence the cervix becomes hard, low and closed. The cervical fluid becomes dense. The cervical plug’s rebuilding lasts around 3 days which are counted into fertile phase. After plugging the cervix we have the infertile phase. The sperm cells are unable to get into the cervix – it’s simply impossible.


Progesterone makes the lining of your uterus soft and spongy so that a fertilized egg can latch onto it and implant. The number of blood vessels supplying nutrients and oxygen is growing. Mucous membrane becomes the first pantry in case of conception and nesting in it a new, developing human life. Progesterone plays the following roles:

  • Progesterone is needed to support and sustain pregnancy.
  • Progesterone causes your Basal Body Temperature (BBT) to rise after ovulation so that it is measurable with a BBT thermometer.
  • Progesterone causes your BBT to stay elevated throughout pregnancy.

One of the characteristic symptoms in this phase, in addition to changes in the cervix and cervical fluid, is a slight shift of BBT. Higher temperature remains through the duration of the luteal phase and drops just before menstruation or in the first days of its duration.

When it comes to the attachment of the fertilized ovum to the endometrium then the temperature remains at a high level for the first 3 months of pregnancy.

If there is no conception progesterone level falls. Mucous membrane begins to atrophy and exfoliate. A new cycle begins.

All symptoms form a group of symptoms characteristic to a particular woman, confirming the impact of hormones on the cycle’s phases.

We have symptoms occurring in every cycle and to every woman. They are the so called main fertility symptoms described above. Among them we have:

  • BBT changes
  • Cervical fluid changes
  • Cervix changes

The fertility methods are based on their cyclical occurrence.

Cyclical changes occurring constantly from the period of adolescence to menopause, also have an impact on the both physical and mental state of a woman.

Menstruation is associated with some discomfort and often also pain. The increase in estrogen is usually time of increased activity, the well-being, positive physical change as better complexion, increase in physical strength, better concentration but it is an individual matter. Some women suffer from the negative signals around ovulation, such as ovulatory pain, heaviness, water retention in the body, constipation, and headaches while some feel the other way round. In the period preceding the menstruation a lot of women experience breast tension, acne or even suffer from severe mental tension, nervousness and so-called premenstrual syndrome (PMS).