The first half of the cycle
The first half of the cycle describes the part of the female cycle in which the eggs mature. This phase is also called the development phase, follicular (maturation) phase, pre-ovulation phase or proliferation phase.

When does the first half of the cycle take place?
The first half of the cycle begins with the first day of menstruation, which is the first day of the cycle. This is because a new cycle of egg maturation already begins with the onset of bleeding. Several eggs then mature at the same time, each in a shell called an ovarian follicle, also referred to as follicle. Only one follicle usually reaches full maturity for ovulation, while the other eggs die. The duration of the first half of the cycle is relatively variable and always ends with ovulation. So for a cycle of 28 days, you would expect it to last about 14 days. For a cycle of 35 days, on the other hand, it would be 21 days.
What happens in the first half of the cycle?
The first half of the cycle is all about the growth and development of the fluid-filled follicle in the ovary and the maturation of the egg inside. The hypothalamus signals the pituitary gland to send FSH to the ovaries to prepare for the release of another egg. In preparation, several follicles begin to swell. The lining of the uterus thickens to later host the egg. During this phase, your physical energy increases and you may sometimes feel a little restless.
The first half of the cycle is too long?
If the first half of the cycle takes a little longer, this is not normally a cause for concern. Stress – even stress that is unconscious or not so obvious – such as an unhealthy diet, high alcohol or caffeine consumption, an excessive amount of exercise, sickness, travelling or an increased workload can prolong the first half of the cycle. However, this usually does not necessarily have an effect on fertility. It usually just means that ovulation takes place a bit later than usual. If that’s the case, this will also delay menstruation a little.
The first half of the cycle is too short?
Basically, you should always look at the overall length of your cycle first to find out if the first half of the cycle is really too short. Cycles that are shorter than 21 days would be referred to as ‘unusually short’ cycles. Some experts in the field of cycle health even describe cycles that are shorter than 24 days as too short. If you ovulate on the 10th day of your cycle or earlier, your body may have released an egg that is not yet fully mature. If the egg hasn’t had enough time to fully mature, it is not fertile.
Which hormones are important in the first half of the cycle?
In the first half of the cycle, the hormones FSH (follicle-stimulating hormone) and LH (luteinising hormone) cause the follicle in the ovary to grow and develop and the egg to mature. More specifically, the hypothalamus signals the pituitary gland to send FSH to the ovaries to prepare for the release of another egg. In preparation, several follicles begin to swell. Estrogen increases to thicken the lining of the uterus.
Progesterone in the first half of the cycle
In the first half of the cycle, the mucous membrane in the uterus (the uterine lining) is built up under the influence of estrogen. Progesterone levels are therefore very low in the first half of the cycle.
In the second half of the cycle, progesterone then prepares the uterus for an implantation of the egg.
Estrogen deficiency in the first half of the cycle
A lack of estrogen in the first half of the cycle can lead to ovulation not taking place. Too little estrogen can also mean that the eggs cannot mature sufficiently or that too little or no cervical mucus is produced. If you want to have a baby, this means that sperm will have difficulty moving around and will have a hard time reaching the egg.
What does cervical mucus look like in the first half of the cycle?
As the follicle grows and prepares for ovulation, the cervical mucus is usually cloudy, whit-ish or yellow-ish and tends to be firm, creamy, thick and not spinnable. As ovulation approaches, the cervical mucus becomes more fluid and the feeling of moisture increases more and more. Directly before ovulation, you can often perceive highly fertile cervical mucus and the largest amount of mucus. This mucus is clear (comparable to raw egg white) and feels slippery. By observing the cervical mucus and the changes every day, you can easily tell whether you are currently fertile or not. It should also be mentioned here that not all women can detect all categories in themselves. Especially after using hormonal contraceptives, many women have problems determining their cervical mucus.