The Follicular Phase: An exciting part of your menstrual cycle

The follicular phase marks the beginning of your menstrual cycle. It starts on the first day of your period and ends with ovulation. This phase is not only the opening act of your cycle but also plays a crucial role in your fertility. It showcases a fascinating interplay of hormones, once again highlighting the incredible superpowers at work in your body every month.

What happens during the Follicular Phase?

Two key processes define this phase of your cycle: menstruation and the maturation of follicles. Let’s break it down step by step to understand what’s happening.

Your period

When fertilization doesn’t occur, the top layer of your uterine lining is shed. This is what you know as your period. During the luteal phase, this lining was built up to support a potential pregnancy, essentially serving as a nest for a possible embryo. However, if your egg isn’t fertilized, the levels of estrogen and progesterone drop, prompting your body to release this top layer. This marks the beginning of the follicular phase ⁽¹⁾.

Follicle maturation and ovulation: A new chapter begins

At the same time, another fascinating process kicks off on the first day of your period: the maturation of your follicles. Under the influence of follicle-stimulating hormone (FSH), tiny fluid-filled sacs, called follicles, begin to develop in your ovaries ⁽²⁾. Each of these follicles contains an egg that is waiting to mature.

Typically, several follicles grow during each cycle, but usually, only one reaches the ideal size and is referred to as the "dominant follicle" ⁽³⁾. This follicle starts producing estrogen, which causes the other follicles to regress. Once estrogen levels are high enough, they trigger a rapid surge of luteinizing hormone (LH), which then initiates ovulation ⁽¹⁾.

What hormonal changes happen during the Follicular Phase?

As you can see, there’s a lot happening during this phase of your menstrual cycle. At the heart of it all are the hormones FSH, estrogen, and LH, working together in perfect harmony.

First, FSH stimulates the maturation of the follicles. Once the dominant follicle is fully developed, it begins producing estrogen. This increase in estrogen suppresses FSH production, ensuring that the other follicles stop growing. The rising estrogen levels then lead to an LH surge, which ultimately triggers ovulation.

It’s a truly remarkable example of the harmonious interplay of hormones within the female cycle!

What symptoms can you experience during the Follicular Phase?

The symptoms you might feel during the follicular phase are as unique as you are. They vary not only from woman to woman but even from cycle to cycle. Below, we’ll outline some common symptoms many women experience during this phase, but always remember: your body is one of a kind, and it will signal what it needs.

During your Period

At the start of the follicular phase, when your period begins, you might experience typical period symptoms. These could include abdominal cramps, bloating, low energy levels, tender breasts, or mood swings ⁽⁴⁾.

It’s essential to never normalize period pain. If you’re experiencing discomfort, it’s important to consult a doctor, as it could be a sign of underlying cycle-related issues.

This is a time to prioritize rest and mindfulness. Listen to your body and take the time to understand what it truly needs during these days, whether it’s some downtime, warmth, or a moment of self-care.

After your Period

Once your period ends, you might notice a shift in your body: a sudden boost in energy levels. You may also observe changes in your cervical mucus. Immediately after menstruation, discharge is often dry or sticky (⁷⁾, and you may notice little to no mucus at all. As you move into the mid-to-late follicular phase, the mucus becomes creamier and white. Around ovulation, you’re likely to notice clear, stretchy mucus, similar to egg whites ⁽⁹⁾.

How can you identify the Follicular Phase using Basal Body Temperature.

One of the most reliable ways to track your follicular phase is by measuring your basal body temperature (BBT)—your lowest body temperature taken immediately after waking up. By consistently recording your BBT over multiple cycles, you can accurately pinpoint the different phases of your cycle.

At the beginning of your follicular phase, during your period, your BBT typically hovers around 97.7°F. and remains relatively low throughout this phase. This stable, lower temperature is due to the dominance of estrogen, as the progesterone surge that raises your temperature hasn’t occurred yet.

The end of the follicular phase and ovulation are marked by a sudden rise in your BBT. When you notice a consistent increase in temperature the next morning, you can be confident that ovulation has taken place. This temperature shift, usually between 0.4 to 1.0°F, is a clear sign that your progesterone levels have risen. It signifies the end of the follicular phase and the transition into the next phase of your cycle, the luteal phase.

How can the Daysy Cycle Tracker support you?

With Daysy, you can accurately track the different phases of your menstrual cycle. This innovative technology not only helps you predict the timing of your period with precision but also allows you to identify your ovulation at a glance. All you need to do is measure your basal body temperature every morning and optionally sync the data with the Daysy app.

Thanks to the precise temperature shifts, Daysy makes it easy to see when you're in the follicular phase. It automatically highlights the temperature drop before your period and the rise following ovulation.

Daysy empowers you to better understand your body, enabling informed and autonomous decisions about your fertility and overall well-being.

 

How long does the Follicular Phase last?

The follicular phase is the longest phase of your menstrual cycle. Its duration varies greatly between individuals and can last anywhere from 10 to 35 days.

While the luteal phase remains relatively consistent throughout your life (lasting 10–16 days), the follicular phase can change depending on your life stage and even vary from cycle to cycle ⁽⁵⁾.

What does it mean if you have a long Follicular Phase?

If your follicular phase is longer, it likely means your overall cycle is longer than the standard 28- to 29-day cycle often used as a reference.

A longer follicular phase doesn’t necessarily indicate difficulties in conceiving. It might simply reflect that your natural cycle is a bit longer. Factors like hormonal contraceptive use or a potential vitamin D deficiency can also extend your follicular phase ⁽⁵⁾.

What does it mean if you have a short Follicular Phase?

In contrast, a short follicular phase could indeed lead to challenges when trying to conceive. It may indicate that your ovaries are aging and that you are approaching menopause, which can begin in your late 30s.

Even if your periods are still regular, your follicular phase may shorten. During this time, the level of follicle-stimulating hormone (FSH) often rises, while luteinizing hormone (LH) levels remain relatively low. This imbalance can cause a follicle to mature too quickly, resulting in an egg that hasn’t reached its optimal developmental stage for fertilization. Consequently, this can reduce your chances of becoming pregnant ⁽⁶⁾.

Cycle tracking: A window into your body

Tracking your cycle is like having a window into your body’s subtle changes that you might not notice otherwise. By consistently monitoring your cycle, you can detect if your follicular phase is shortening, giving you valuable insights into what’s happening internally.

This information can help you better understand hormonal imbalances or age-related changes in ovarian function. Armed with this knowledge, you can speak with your doctor early on and work together to find solutions that support your fertility goals.

Can you get pregnant during the Follicular Phase?

Yes, the most fertile days of your cycle occur during the follicular phase. If you wait for ovulation, you’ll only have about 12 to 24 hours for fertilization ⁽¹¹⁾. However, since sperm can survive in the female body for up to five days ⁽¹⁰⁾, your fertile window actually begins a few days before ovulation, while you’re still in the follicular phase.

If you’re trying to conceive, it’s essential to make the most of this fertile window in the follicular phase. On the other hand, if you wish to avoid pregnancy, you should abstain from sex during this time or use an additional barrier method, such as condoms.

Fertilization itself, however, always occurs after ovulation, during the luteal phase.

Your path to greater understanding and self-empowerment

The follicular phase marks the beginning of every cycle and serves as an impressive example of how complex and fascinating your body works. By delving deeper into this phase, you can gain a better understanding of your body’s natural processes, support them intentionally, and positively influence your health. At the same time, this knowledge gives you the opportunity to consciously and autonomously manage your fertility.

We hope this information can support your personal life plan, whether you are currently trying to conceive, aiming to avoid pregnancy, or simply looking to develop a deeper awareness of your cycle.

Sources: 

⁽¹⁾ McLaughlin, J. E. (2022, September 12). Menstruationszyklus. MSD Manual Ausgabe Für Patienten. https://www.msdmanuals.com/de/heim/gesundheitsprobleme-von-frauen/das-weibliche-fortpflanzungssystem/menstruationszyklus

⁽²⁾ Menstruationszyklus. (2023, October 5). Kenhub. https://www.kenhub.com/de/library/anatomie/ovarialzyklus

⁽³⁾ Ivi. (2024, March 25). Follikel: Wie viele sind normal? IVI DE. https://ivi-fruchtbarkeit.de/blog/follikel/

⁽⁴⁾ Hollowood, K. (2024, July 9). What is the follicular phase? Know your cycle and symptoms. Flo Health. Retrieved January 10, 2025, from https://flo.health/menstrual-cycle/health/follicular-phase

⁽⁵⁾ Cleveland Clinic Medical. (2024, July 3). Follicular phase. Cleveland Clinic. Retrieved January 10, 2025, from https://my.clevelandclinic.org/health/body/23953-follicular-phase

⁽⁶⁾ Watson, S. (2018, August 18). All about the follicular phase of the menstrual cycle. Healthline. https://www.healthline.com/health/womens-health/follicular-phase#temperature

⁽⁷⁾ Najmabadi, S., Schliep, K. C., Simonsen, S. E., Porucznik, C. A., Egger, M. J., & Stanford, J. B. (2021). Cervical mucus patterns and the fertile window in women without known subfertility: a pooled analysis of three cohorts. Human Reproduction, 36(7), 1784–1795. https://doi.org/10.1093/humrep/deab049

⁽⁸⁾ Hatcher RA, Nelson AL, Trussell J, et al. Contraceptive Technology (21st edition). New York: Ayer Company Publishers. 2018.

⁽⁹⁾ Rao VL, Mahmood T. Vaginal discharge. Obstetrics, Gynaecology & Reproductive Medicine. 2020 Jan 1;30(1):11–8

⁽¹⁰⁾ Gargoyle, P. (2022, May 5). Sperm: How long do they live after ejaculation? Mayo Clinic. Retrieved January 10, 2025, from https://www.mayoclinic.org/healthy-lifestyle/getting-pregnant/expert-answers/pregnancy/faq-20058504

⁽¹¹⁾ Cleveland Clinic. (2024, May 1). Luteal phase. Retrieved January 10, 2025, from https://my.clevelandclinic.org/health/articles/24417-luteal-phase