Your hormones are constantly shifting throughout your menstrual cycle.
Oestrogen rises. Progesterone rises and falls. FSH helps recruit and develop follicles. LH surges to trigger ovulation.
And these hormonal changes can influence everything from your cervical mucus and body temperature to your energy, mood, appetite and the arrival of your next period.
Understanding the basic pattern can make your cycle feel a lot less mysterious.
So, let’s walk through what’s actually happening.
First, meet the four key hormones
Before we look at each phase, there are four hormones worth knowing.
FSH: Follicle-stimulating hormone
FSH is released by the pituitary gland in your brain.
At the beginning of your cycle, FSH helps stimulate a group of follicles in your ovaries to develop. Each follicle contains an immature egg.
Eventually, one follicle usually becomes dominant and continues developing towards ovulation.
Oestrogen
As the developing follicle grows, it produces increasing amounts of oestrogen, particularly estradiol.
Oestrogen helps rebuild and thicken the lining of the uterus after your period and plays an important role in preparing the body for ovulation.
LH: Luteinising hormone
LH is also released by the pituitary gland.
When oestrogen remains high enough around the middle of the cycle, it helps trigger a rapid rise in LH known as the LH surge.
That surge is what triggers ovulation.
Progesterone
After ovulation, the follicle that released the egg transforms into a temporary structure called the corpus luteum.
The corpus luteum produces progesterone.
Progesterone helps maintain the uterine lining and prepare it for the possibility of implantation and pregnancy.
Now let’s put those hormones into the context of your cycle.
Phase 1: Menstruation
What’s happening: Your period begins.
Day one of your menstrual cycle is considered the first day of full menstrual bleeding.
If pregnancy hasn't occurred in the previous cycle, the corpus luteum breaks down. As a result, progesterone and oestrogen levels fall.
That hormonal drop signals the uterine lining to shed, resulting in your period.
At the same time, FSH begins to rise again, helping recruit follicles for the new cycle.
So even while you're bleeding, your body is already preparing for what comes next.
Hormone snapshot:
Oestrogen: Low
Progesterone: Low
FSH: Beginning to rise
LH: Relatively low
Phase 2: The follicular phase
What’s happening: An egg is developing and oestrogen is rising.
Technically, the follicular phase begins on the first day of your period and continues until ovulation. But once menstruation finishes, the hormonal changes of this phase become much more noticeable.
FSH encourages ovarian follicles to develop.
As a dominant follicle emerges and matures, it produces increasing amounts of oestrogen.
That rising oestrogen helps rebuild the endometrium, or uterine lining, after menstruation.
You may also begin noticing changes in your cervical mucus as ovulation approaches. It typically becomes wetter, clearer and more slippery, creating an environment that helps sperm move through the reproductive tract.
Hormone snapshot:
Oestrogen: Rising
Progesterone: Low
FSH: Supports follicle development, then generally declines
LH: Gradually rising
Phase 3: Ovulation
What’s happening: The mature egg is released.
As oestrogen rises and remains elevated, something interesting happens.
Instead of suppressing FSH and LH as it usually does, sustained high oestrogen creates positive feedback that triggers a significant surge in LH.
This LH surge triggers the dominant follicle to release its egg from the ovary.
That is ovulation.
The egg then enters the fallopian tube, where fertilisation may occur if sperm are present.
Ovulation doesn't necessarily happen on day 14. The timing varies between women and can also vary from cycle to cycle.
Hormone snapshot:
Oestrogen: Peaks around ovulation, then briefly falls
Progesterone: Still relatively low but beginning to rise
FSH: Has a smaller mid-cycle surge
LH: Surges dramatically
Phase 4: The luteal phase
What’s happening: Progesterone takes the lead.
Once ovulation has occurred, the emptied follicle becomes the corpus luteum.
This is where progesterone becomes the dominant hormone.
Progesterone supports and stabilises the uterine lining, preparing it for the possibility of implantation.
It also causes a small rise in basal body temperature, which is why tracking temperature can help confirm that ovulation has occurred.
Oestrogen also rises again to a smaller second peak during the luteal phase.
If fertilisation and implantation occur, hormonal signalling helps maintain the corpus luteum so progesterone production can continue during early pregnancy.
If pregnancy doesn't occur, the corpus luteum naturally begins to break down.
Hormone snapshot:
Oestrogen: Moderate, with a smaller second rise
Progesterone: High
FSH: Low
LH: Low
Then the cycle begins again
If pregnancy hasn't occurred, the corpus luteum breaks down and progesterone and oestrogen fall.
Without those hormones maintaining the uterine lining, it begins to shed.
Your next period starts.
And we return to day one.
The cycle begins again.
Your hormones don't work in isolation
It's easy to think about oestrogen, progesterone, FSH and LH as four separate hormones.
But your menstrual cycle is really a carefully coordinated conversation between your brain, pituitary gland and ovaries, often referred to as the hypothalamic-pituitary-ovarian axis.
One hormonal change influences another.
FSH helps develop the follicle → the follicle produces oestrogen → high oestrogen helps trigger the LH surge → LH triggers ovulation → the corpus luteum produces progesterone → progesterone supports the uterine lining.
When pregnancy doesn't occur, oestrogen and progesterone fall, menstruation begins, and FSH starts preparing another group of follicles.
What does a “normal” cycle look like?
There isn't one perfect menstrual cycle that every woman should have.
Cycle length, bleeding patterns and symptoms can vary between individuals and even between cycles.
And despite the classic diagrams showing ovulation neatly occurring on day 14 of a 28-day cycle, real bodies don't always follow a textbook calendar.
This is why understanding your individual pattern can be more useful than comparing your cycle to a single “ideal”.
What we look at at Floura
When we're assessing menstrual or hormonal health, we're interested in more than whether your period arrives each month.
We might ask:
How long is your cycle?
What does your bleed look like?
Are you experiencing spotting?
Do you notice signs of ovulation?
What happens in the week before your period?
Are your cycles changing?
Are you experiencing pain, mood changes or other symptoms?
And where appropriate, pathology testing can provide further information.
Importantly, the timing of hormone testing matters.
Because your hormones are supposed to change throughout your cycle, a hormone result without knowing where you were in your cycle can be difficult to interpret meaningfully.
The takeaway
Your menstrual cycle isn't simply the few days you have your period.
It's a continuous hormonal rhythm.
FSH helps prepare the follicle.
Oestrogen rises as the follicle develops.
LH surges to trigger ovulation.
Progesterone rises after ovulation.
And if pregnancy doesn't occur, oestrogen and progesterone fall, triggering your next period.
Understanding that pattern gives us valuable context when we're looking at periods, ovulation, fertility and hormonal symptoms.
At Floura, we don't just ask whether you're getting a period.
We're interested in what your whole cycle might be telling us.
This article is for educational purposes only and does not replace individual medical advice, diagnosis or treatment. If you're experiencing significant changes to your menstrual cycle, absent or very irregular periods, heavy bleeding, severe pain or other concerning symptoms, speak with an appropriately qualified healthcare professional.