If you’re anything like me, the female ovulation cycle can be outright baffling. Certainly in my early years, the months would roll by and I would have no idea that my body was going through a tidal wave of hormones. I would go from one period to the next just grateful for the break from bleeding!
But in fact, there’s a whole host of fertility hormones coming from the ovaries and the brain, which transform the uterus throughout the cycle. Here’s a run down the female ovulation cycle and the key hormones and phases at play. Hang in there, there’s a bit to cover, but it’s worth it!
Day 1 = Menstruation, start of the Follicular Phase
Day 1 of your cycle is hard to miss- it is measured as the FIRST day of your period. Women can menstruate for any number of days, but usually it lasts between 3 and 7 days.
Menstruation is the body shedding the inner lining of the uterus, the Endometrium. The Endometrium grows throughout the cycle, preparing to host a fertilized egg. But in the event you are not pregnant, the whole lining is shed by menstruation and a new lining is created during the next cycle.
Once your body has finished shedding the Endometrium and your bleeding has stopped, your ovaries are in full swing getting ready for ovulation, but I’ll come to that in a bit…
The Follicular Phase, as indicated in the name, is all about the follicles in the ovary getting mature enough to release the egg. Strictly speaking it lasts from Day 1 (menstruation) until Ovulation (the release of the egg from the ovary), and the length of this phase varies for every women. This phase of your cycle can last anywhere from 7 to 40 days and not only varies for each woman, but can vary each cycle.
There is a raging cascade of hormones at play in this phase. Oestrogen is the main player and rises steadily in the blood stream, resulting in a surge usually around Day 7 (for a 28 day cycle).
Oestrogen really is KEY and it does the following things:
It nourishes and stimulates the growth of the Endometrium in the uterus and,
It stimulates the production of another hormone, gonadotrophin releasing hormone (GnRH), which in turn increases the production of luteinising hormone (LH).
LH is what triggers ovulation!
The Hormone Cascade
Are you still with me?? It’s just getting to the exciting bit, so hang in there…
So, what on earth is happening with all these hormones? Firstly there is a surge in oestrogen (around day 7), and then 2 or 3 days later there is a surge in LH, and then approximately 30 hours after that LH surge, OVULATION occurs and that tiny egg is finally released from the ovary. Phew!!
After that teeny tiny egg is released, the oestrogen and LH levels drop off a cliff and the next raging hormone, Progesterone, starts to rise rapidly.
After Ovulation = Luteal Phase!
So this brings me to the second exciting phase of this magical cycle…the Luteal Phase.
This phase is measured from the day of Ovulation until the start of your next period. This is more of a FIXED phase, meaning, it is roughly the same length each cycle. That means, if you ovulate, you’ll be pretty sure to menstruate roughly 14 days later every time. So, in a 28 day cycle, we would expect ovulation to occur on Day 14, and your next period to start 14 days after that.
The KEY hormone here, Progesterone, is released during this phase. It comes from the remaining bit of the follicle on your ovary (ie, the casing of the egg that was released, known as the corpus luteum).
Progesterone works to ripen the Endometrium, getting it nice and thick to prepare for pregnancy. This happens regardless of whether you are pregnant or not. And guess what, when the corpus luteum stops producing progesterone (usually 14 days after ovulation), and if you are NOT pregnant, menstruation starts again. And so we are back to where it all began.
Honestly, I could write a whole other chapter on the luteal phase, as this phase tells us a lot about your fertility…but I’ll save that for another day.
For now, let’s just recap:
Your cycle can be divided into the Follicular and Luteal Phases
Day 1 of your cycle = menstruation, and the start of the Follicular Phase
Ovulation occurs after a massive surge in oestrogen and LH
The Luteal Phase is measured from the date of Ovulation until Menstruation starts again
I’m not so sure I’ve made it any less baffling for you, but here’s to starting the conversation and working out how your cycle works for you.
This article is for educational purposes only. It is not meant to diagnose any condition or act as a replacement for a medical consultation.