The information in this podcast is provided for education and research information only. It is not a substitute for professional health advice.
Welcome everyone, I'm Brigid Maloney and today I've got a quick kick for you, and it's all about the menstrual cycle. So in twenty twenty two we released only one episode for the entire year. It was a massive year for us, both professionally and personally. Our eldest boy went off to college and we were busy building our new women's health clinic.
And that is learning about your menstrual cycle for something that is regular, and I'm going to say for most people, having a great and full understanding of your menstrual cycle is not common. The questions you ask us about how to get pregnant is not in the high school curriculum. What is, though, is how not to get pregnant. Which I don't know about you, but in my high school learning, it made me think that anytime I would have sex
it would lead to a pregnancy. It comes as a surprise to some then when I are trying for a baby that that actually isn't the case. The first step to getting pregnant has to be to get to know your menstrual cycle. So let's get into it. Pat suggests you look at a chart of the menstrual cycle when listening to this episode. You can find one on our website grow mybaby dot com dot au or in the link in the show notes of this app. Let's start learning.
So I think it's easiest to understand not worrying too much about this phase and that phase that you'll see in those diagrams and the year ten science textbook diagram of the cycle, but really to think of it in terms that ordinary people would experience, which is the cycle itself and the days of the cycle. So day one is the start of the cycle, and that's the first day of bleeding. It's called the menstrual phase, if you
need to give it a name. And at the stage of the cycle, all the hormones are sitting there pretty low, the bleeding is actually happening. After a few more days, a hormone starts coming out of your brain called FSH follicle stimulating hormone, And what that hormone does is stimulates some of those deep follicles, the little tiny sacs that
are going to eventually contain a mature egg. Now you've got hundreds of thousands of those little follicles, and under the influence of FSH hormone in those early days of the cycle, one of them gets matured up above the rest and becomes what I call the chosen one for the month, and that's the one that's actually going to have a mature egg inside it, mature enough to actually
be ovulated out in the middle of the cycle. During that phase, when the follicle is developing and the chosen one is chosen and the egg is maturing, the over is also producing estrogen, and the estrogen is making the lining of the uterus thicker. About day thirteen, a second hormone kicks in from the brain called l H and that's the one that those ovulation predicted gates can test for. And what it does is cause the final maturation of the follicle and the egg such that the egg is
ready to be released the following day. After the LHED surge, which is in a textbook cycle, about day fourteen, so out pops the egg on day fourteen. The egg starts its journey out towards the Filippian tubes, hoping that the fingers on the edge of the Filippian tubes will catch it and direct it down the tube, where if we're trying to get pregnant, might meet up with some sperm
company other way in the tube. In the tube. Yeah, So when the egg pops out the surface of the ovary, the mature follicle that let go of the egg, the rest of it turns into a structure called corpus lute and the corpus lutine is a little structure on the surface of the ovary that's main job is to produce
tons of progesterone. And the second half of the cycle, everything after the ovulation day is kind of dominated by a progesterone from the corpus luteum, and that progesterone's job is to stabilize the menstrual lining in the second half of the cycle and get it ready for the implantation of the egg. If the egg happens to get fertilized, so for fertilized egg implants, then the pregnancy is off
from there. And assuming that pregnancy doesn't take place, then eventually the corpus luteum runs out of function, gets smaller, and disappears. The progesterone level goes right down and the bleeding starts again and that's the new day one. Whole process is repeated.
So even though you know you said day one, at day one, yes, all the hormones are low, when did you say the hormones start kicking in again.
Well, estrogen rises progressively through the first half of the cycle and peaks around the middle, and progesterone is the dominant hormone of the second half of the cycle.
The whole thing, there's so many moving parts, isn't there?
There are so understanding that explanation. One of the useful things you could do is get out that old high school science diagram of how the cycle works, and maybe we'll attach that to the show notes so that people could look at that diagram and listen to me explain how.
That works opefully at the same time, Yeah, at the.
Same time, and understand that process.
All right, So does a woman's cycle sort of change throughout her life?
Yeah? Absolutely so. It definitely changes throughout a woman's life. And that can also help us understand some of the ways in which menstreul issues might be causing a problem or might present if woman needs to go to a doctor about one of these issues. So let's look at the first stage of pre puberty. At that stage, those FSH and LH hormones are just not coming out of the brain to stimulate the cycle. So that's why it's no period. Anatomically, a woman's got ovaries and a young uterus,
but they're not being stimulated. At puberty, FSH and LH start being produced in the brain stem, come down to the ovaries and start the start of a cycle. Now they will stimulate the ovary to start functioning hormonally, but they don't often result in full ovulation in the first couple of years, and that's because the hormonal processes here are pretty complicated and they take it quite a while
to establish their full functionality. So you'll get some periods in that first couple of years that can be annalvulatry no egg, and it's often described as being an immature
relationship between the brain and the ovaries. So when those cycles result without an egg, then just like any other annalvulatory cycle, they can be problematic, irregular, too heavy, and so we do see adolescent whemen for menstrual disturbances if they're quite significant, and sometimes we can treat those by replacing the lack of natural progesterone in the second half of the cycle because there's no egg, so there's no corpusly team, so there's no progesterone with some artificial registerone
from a source like a contraceptive pill.
Yeah right, just bank that information. They might be handy for all these women that are having daughters for later.
Yeah. So the first couple of years, as few as ten percent of the cycles fully mature ovulatory cycle. So then we get past those first couple of years and just move into normal menstrual years, which might go from fifteen or so to about forty five forty six. And in those years, the menstrual cycle is working in a totally normal situation. It's working normally. The hormonal cascade that I mentioned before is functioning normally, and the cycle is
functional and the woman is fertile. After that, in the late forties, so called perimenopause will change. We start to see the ovary being unable to fully respond to stimulation from the brain such that some months there's no egg. So we might have ten ovulatory cycles a year and two an olphilatory cycles. Those and ovulatory cycles will typically have issues with heavy bleeding or a cycle that's way too long, followed by a heavy period. We might be
able to put up with the odd one. But as the ovary is increasingly unable to ovulate each month, then menstrual disturbance related to an ovulation becomes more common, and we're much more likely to see women at that time with issues of heavy or irregular menstrual periods. One more phase we didn't talk about, and that's metopause. So menopause comes.
It's commonly thought of being when you run out of eggs, and it's not really running out of eggs, it's just when the ovary gets to the point where it can't respond at all to the stimulation from the brainstam. Once it's done, doesn't matter how much the FSH and LH hormones coming out of the brain say, come on, overdo something.
It can't anymore. And so there may still be vollicles left in the ovary, but the over is no longer capable of maturing them up, so that at that point hormonal production from the ov receases, and I'll see women of course at that stage of life, not so much a problem that the ovary can't produce hormones anymore, but the rest of their body might miss the estrogen. So we sometimes see people who've sailed through the menopausal transition
without an issue. But sometimes I'll see women who are having typical responses from the rest of their body to the lack of estrogen being secreted by the overary, so hot flushes, sleep disturbance, breast tenderness, drive vagina, and so forth.
Thanks for joining us. If you have more questions about the menstrual cycle, we would love to hear them. Pop onto our website grow mybaby dot com dot you and put your question on speak pipe. There are no silly questions. We are all here to learn and if you have a question, chances are someone else will have the same question, so you'd be the brave one and ask it for them. For those who are trying for a baby, come and
join our Getting Pregnant program. This is all the pre pregnancy information that you and your partner need to know to help you optimize your chance of for pregnancy. You can find the links to this on our website grow mybaby dot com dot AU and in this EPs show notes. Until next week, Keep well life now