The follicular phase

This phase in the female cycle is all about the growth and development of the follicle in the ovary and the maturation of the egg.

The follicular phase is often also called the growth phase, follicle maturation phase, preovulation phase or proliferation phase. Symbolically, this phase of the cycle corresponds to spring. Energy levels slowly rise again and we feel increasingly open to new things.

In this phase of the cycle, the lining of the uterus rebuilds after menstruation and at least one egg matures. Hormone levels rise. 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 with the increase in estrogen so that it can subsequently host an egg.

In the follicular phase:

• the reproductive hormones (at the beginning of this phase) are at their lowest level (where they were during menstruation)
• estrogen begins to rise (in the second part of this phase) 
• the lining of the uterus begins to thicken
• the ovaries prepare to release an egg (i.e. ovulation) 
• metabolism is slower and cortisol levels are lower
• no significant amounts of progesterone or testosterone are produced. Some women may feel a little tired during this phase of the cycle if their hormones are not in balance.

The duration of the follicular phase usually refers to the 7 to 10 days after your period ends.

We always recommend looking at the total length of the cycle to see if the follicular phase is really too short. Cycles that are often shorter than 21 days in total are referred to by science as cycles that are ‘too short’. Some experts in the field of cycle health also think that cycles that are shorter than 24 days are ‘too short’. A short follicular phase may very well mean that the body has released an egg that is not yet fully mature. Conversely, if the egg is not yet fully formed, it is usually not fertile.

If the follicular phase lasts a little longer, this usually isn’t a cause for concern. Stress – even stress that is unconscious or not quite so obvious – such as an unhealthy diet, high alcohol or caffeine consumption, too much exercise, illness, travelling or an increased workload can prolong the follicular phase. This also means that ovulation will take place a few days later than usual. By the way, this also means that menstruation will be delayed a little. If the follicular phase is often too long, you should take a closer look at your own habits to see if there is a need for optimisation. Science also associates low vitamin D levels with a prolonged follicular phase.

The last few days of menstruation could very well be considered an early follicular phase, because a new cycle of egg maturation already begins with menstruation. Several eggs then mature at the same time, each in the ovarian follicle, which is also called a follicle.

The egg can be fertilized for up to 24 hours after it is released into the fallopian tube. If ovulation has taken place, fertilization can only take place within this window of time, because strictly speaking a woman is only fertile at this time. However, sperm can survive in the woman’s body for up to five days under ideal conditions, extending the fertile phase, which is limited to just 24 hours, to up to six days. This means that, taking into account the viability of the sperm, the five days before ovulation and the day of ovulation (due to the viability of the egg) are defined as the woman’s fertile days. Unprotected sexual intercourse is significantly more likely to result in conception during this time than on other days in the cycle.

The hormones FSH (follicle-stimulating hormone) and LH (luteinising hormone) cause the follicle to grow and develop in the ovary and the egg to mature. 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.

In the follicular phase, the hormone estrogen plays a predominant role. Progesterone levels are therefore very low in this phase of the cycle. In the second half of the cycle, progesterone then prepares the uterus for a possible implantation of the egg.

The most important (naturally occurring) estrogens in the body are estradiol, estrone and estriol. Together with the progestins, they control all processes in the female cycle and in reproduction. If not enough estrogen is produced in the follicular phase, this 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. In the case of conception, this leads to sperm having a harder time moving around and having a hard time getting to the egg.

During this phase of the cycle, it’s best to focus on foods that are rich in protein. This helps build up the uterine lining. Probiotic foods can also help your body process the increased hormone levels. Flaxseed, lentils and fermented foods should be on your plate more often during this time.

In the follicular phase, your body is focused on building and growing. Carbohydrates can now be better tolerated, especially after exercise, and muscles can be built more easily. Research has also shown that muscle strength is increased in the follicular phase. That means that this phase is good for demanding workouts.

The rise in estrogen makes this phase perfect for planning and new ideas. Symbolically, this is a phase of new beginnings. It’s a good time for challenging tasks and new projects. As the follicular phase progresses, you feel that you want to spend more time with other people again and feel increasingly social.

For most women, the follicular phase is probably the “happier” time in the cycle, especially compared to the second half of the cycle. The feeling of happiness in the first half of the cycle is partly due to hormonal changes in brain chemistry. The rise of estrogen in the body can also help to dampen the effects of the stress hormones adrenaline and cortisol.