Your ovarian cycle and menstrual cycle phases explained

Your ovarian cycle and menstrual cycle phases explained

Menstrual and ovarian cycles 101: what happens in your body.

Curious to learn more about your menstrual cycle and ovarian cycle? At Modibodi, we’re big believers in understanding how our bodies work.

In a nutshell, the menstrual cycle is a natural process that prepares bodies for pregnancy. (And as you might’ve guessed, it happens whether you’re planning on having a baby or not.) If you don’t end up getting pregnant, your hormones tell your uterus to shed its lining, which becomes your period. Once your period begins, the cycle starts again.

But, as we’ll get into, there’s a lot more to the picture than just your period.

The 4 phases of the menstrual cycle

Your menstrual cycle goes through 4 key phases from the day your period arrives to the first day of your next period. The ovarian cycle is what happens in your ovaries during the menstrual cycle.

On average, menstrual cycles take place over the course of 28 to 29 days, but their length and intensity can vary from person to person.

Here’s what happens in your body during each phase.

Menstrual phase (lasts 3–7 days)

If an egg from your previous cycle hasn’t been fertilised, your body will shed the thickened lining of your uterus, which was there to nurture the egg. This shedding is what many of us know as our period.

The arrival of your period (made up of blood along with some mucus and tissue) through your vagina marks the start of the menstrual cycle.

Follicular phase (lasts 11–27 days)

The follicular phase starts in tandem with the menstrual phase, meaning it overlaps with the early stages of your period. During this phase, your brain releases follicle-stimulating hormone (FSH), which prompts your ovaries to produce a batch of tiny sacs known as follicles. Inside each follicle is an immature egg.

Typically, only the strongest, healthiest egg will have the chance to grow (though sometimes two make the cut). As the egg matures, your estrogen levels rise, and your uterus lining thickens.

Ovulation phase (lasts 16 to 32 hours)

Surging estrogen levels now stimulate your brain to release luteinising hormone (LH), and ovulation begins. The matured egg leaves the ovary and travels along a fallopian tube, headed for your uterus in the hopes of hitting it off with a sperm.

Ovulation tends to happen in the middle of your cycle, a couple of weeks before your next period. Some telltale signs you’re ovulating include:

  • A minor increase in basal body temperature (your at-rest temperature)
  • Thicker discharge in your underwear (think egg-white texture)
  • Not one to wait around, the egg will disintegrate if not fertilised after one day.

    Luteal phase (lasts 11 to 17 days)

    The luteal phase is when your body does a hormonal pregnancy test of sorts. After ovulation, the follicle that released the egg transforms into a structure called the corpus luteum. This temporary gland secretes a hormone called progesterone, plus some estrogen, to keep your uterus lining thick and egg-ready.

    If you get pregnant, your body will start making human chorionic gonadotropin (hCG), which helps keep your uterus lining thick. It’s also the hormone pregnancy tests look for.

    If you don’t conceive, the corpus luteum vanishes back into the body, and your estrogen and progesterone levels drop, triggering the arrival of your period. If you get premenstrual syndrome (PMS) symptoms, this is when they generally show up.

    More on hormones

    Hormones are at the heart of the menstrual cycle. Think of them as chemical messengers giving individual parts of your reproductive system the go-ahead to do their thing when the time is right.

    As we’ve discovered, there are a bunch of hormones (like FSH, LH and hCG) that work together in each phase of your cycle to make fertility possible. But we dare you to name a more iconic duo than estrogen and progesterone. These busy-body hormones are fairly well known for their roles in the menstrual cycle, but they do a lot more to maintain the overall health of menstruating and non-menstruating bodies alike.

    What estrogen does

    Estrogen plays an important role in sexual and reproductive development during puberty. It also keeps the menstrual cycle running smoothly and supports fertility and pregnancy.

    What’s more, estrogen helps:
    • Maintain healthy cholesterol levels
    • Prevent bone loss
    • Reduce the effects of ageing on your skin
    • Ensure optimal brain and heart function

    If you’ve noticed you get irritable, anxious or weepy in the lead-up to your period, know that there’s a relationship between menstrual cycle hormones and mood. Sometimes, lower estrogen levels in your luteal and menstrual phases can bring on PMS symptoms like mood changes.

    What progesterone does

    Quick recap – remember the temporary gland from your luteal phase? The one that sounds like a magic spell? This (the corpus luteum) is what produces the steroid hormone progesterone to prep your uterus for pregnancy.

    If your egg goes unfertilised, your progesterone levels will drop and prompt your period to begin. If the egg is fertilised, progesterone gets to work, helping your uterus to nourish the developing fetus.

    Progesterone promotes wellbeing in many ways, helping to keep bones strong, encourage restful sleep and keep depression at bay.

    In menstruating bodies, a lack of progesterone may result in:

    • Inconsistent or skipped periods
    • Unusual periods
    • Elevated estrogen levels (which can lead to loss of libido, weight gain and gallbladder issues)
    • Spotting and abdominal pain when pregnant
    • Recurring miscarriages

    7 things that can mess with your cycle

    Human bodies are as unique as fingerprints. Everyone’s cycle is different and can change through each stage of life for many reasons.

    Known disruptors of the menstrual cycle and ovarian cycle include:

    • Pregnancy. The OG disruptor, pregnancy should put a stop to your periods.
    • Birth control. Contraceptives like the pill may make periods shorter, lighter or even absent.
    • Uterine fibroids. These noncancerous growths can appear in your uterus and make your periods heavier and longer.
    • Polycystic ovary syndrome (PCOS). This hormonal imbalance interrupts the development of an egg in the ovaries and may trigger menstrual irregularities.
    • Rigorous exercise. Too much high-intensity exercise may cause your period to stop.
    • Weight changes. Weight changes can impact estrogen levels, with excess fat or rapid weight loss sometimes leading to heavy, missed or irregular periods.
    • Stress. High stress levels may lead to painful periods, erratic bleeding and fertility challenges.

    From fluctuating hormones to breastfeeding, poor sleep and health conditions, there are many reasons your cycle might deviate from its normal rhythm. If you’re worried, your GP is the best person to turn to.

    What is menstruation leave?

    Menstruation leave is a type of workplace leave where employees can take time off due to menstruation-related symptoms (like PMS). In Australia, a group of unions are working to get menstruation leave into the Fair Work Act.

    If you’ve ever been struck with sucky period symptoms like cramps, headaches or nausea and just couldn’t make it to the office or even your WFH desk, you’re not alone. In 2021, 40% of the 125,000 Bloody Big Survey participants said they have called in sick because of their period.

    If the unions succeed in getting menstruation leave into Australian legislation, workers will get one day of paid leave a month. We’re rooting for them, especially considering that 77% of Australian women say period pain has affected their ability to work.

    In the meantime, some companies are introducing their own menstrual leave policies for workers. And, of course, Modibodi is proudly among them.

    Get to know your menstrual cycle even better

    Hopefully, you’re feeling better acquainted with your menstrual cycle and everything that goes on during each of its phases. And if you now have more questions than you did when you started reading, we don’t blame you!

    Though it can sometimes be a (literal) pain in the bum, our cycle is a fascinating, intricate process that warrants investigation. Discover more about the nitty-gritty of it all on the Modibodi blog.



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