WHAT’S ON A CHART?

Our charts are where we record everything that we observe about our fertility and our bodies at the end of each and every day.

Watch the video above for an explanation of all the different components of your chart.

First: A Quick Recap of our ovarian hormones

Our ovaries produce oestrogen and progesterone. These are our ovarian hormones.

Oestrogen is produced by the follicles in our ovaries as they grow larger in the lead-up to ovulation. Our bodies produce 3 types of oestrogen – but estradiol is the type that is produced in our ovaries. When I refer to oestrogen throughout this course, I’m referring to estradiol.

Progesterone is produced by the corpus luteum (which is the temporary endocrine structure that forms from the follicle that the egg emerged from at ovulation). The corpus luteum also produces moderate levels of oestrogen.

Oestrogen causes the lining of the uterus to grow. It also affects the cervix and the mucus that the cervix produces. Oestrogen is also responsible for breast development and our female secondary sex characteristics.

Progesterone causes the lining of the uterus to thicken in preparation for a potential pregnancy. It also causes our core body temperature to rise. Progesterone is known as the “pregnancy hormone” because it primes the body for a potential pregnancy. In simple terms, the word progesterone is derived from the term “pro-gestation”.

 

But what causes our follicles to start growing larger and making oestrogen in the first place? And what triggers the egg to burst out of one of these follicles so that the corpus luteum can form?

Welcome to the HPO axis – it turns out, your BRAIN is the CONTROL CENTRE of the menstrual cycle!

HPO stands for Hypothalamic-Pituitary-Ovarian axis.

Your HPO axis is made up of three different body parts:

1. Hypothalamus
2. Pituitary Gland
3. Ovaries

 

The hypothalamus is a small region in the centre of your brain. It is tasked with keeping your body in a state of balance. It does this by sending out hormonal messages into the bloodstream via the pituitary gland.

The pituitary gland is a pea-sized gland that is connected to the hypothalamus by a stalk. The pituitary gland creates different hormones for all different parts of the body. The hypothalamus sends different types of “releasing hormones” to the pituitary gland, telling the pituitary gland to release different types of hormones depending on what is needed in the body.

 

The hypothalamus and the pituitary gland are connected to our ovaries through a complex feedback loop of hormones. These hormones are in a constant dance – a small change in the level of one hormone, will create a counter-change in the level of another hormone. In this way, our HPO axis is the conductor of a cascade of hormones each menstrual cycle.

The reproductive hormones that the pituitary releases (when told to by the hypothalamus) are called “pituitary hormones.” The pituitary hormones are:

1. Follicle Stimulating Hormone (FSH), and
2. Luteinising Hormone (LH)

The hypothalamus controls the release of FSH and LH by sending out regular pulses of gonadotropin-releasing hormone (GnRH) to the pituitary gland. GnRH tells the pituitary to release FSH and LH.

 

Follicle Stimulating Hormone

Follicle stimulating hormone (FSH) stimulates a group of follicles to begin growing in our ovaries each menstrual cycle.

As these follicles grow larger, they produce more and more oestrogen.

Oestrogen has a negative feedback effect on FSH. When oestrogen levels are high enough, levels of FSH are suppressed.

 

luteinising Hormone

When oestrogen reaches peak levels in your bloodstream, the hypothalamus is alerted. The hypothalamus signals the pituitary to produce a surge of luteinising hormone (LH).

LH triggers the first division of the egg inside the dominant follicle. LH also triggers the egg to burst out of the follicle. Finally, LH also causes the cells of the follicle to transform into the temporary endocrine gland: the corpus luteum.

During the luteal phase, the corpus luteum produces high levels of progesterone and moderate levels of oestrogen. When high enough, progesterone and oestrogen have a negative feedback effect on the hypothalamus and pituitary. Oestrogen and progesterone stop any further pulses of LH or FSH. This means that it is not possible for a second ovulation to occur outside of the 24 hour window of ovulation.

 

Getting Started

At puberty, the HPO axis has to begin functioning for the first time ever! It takes some time for the hormonal messaging systems to regulate. This is why many teenagers experience irregular cycles and heavy bleeding during the first few years of puberty. In many cases, they just need some time (and diet/ lifestyle/ supplementation support) for their brain-ovary communication to stabilise.

 

While this may all seem a little confusing – you really only need to remember these three main points:

1. FSH causes groups of follicles to grow in your ovaries
2. LH surges just prior to ovulation and is what triggers ovulation
3. After ovulation, oestrogen and progesterone suppress FSH + LH. This means the 24-hour event of ovulation can only occur once each menstrual cycle (although multiple eggs can be released during this 24 hours).

 

One last important thing to note is that a surge of luteinising hormone (LH) doesn’t guarantee that ovulation will occur. It just means that your body is going to try to ovulate. There’s always a chance that the ovulation attempt will not be successful. However, if ovulation does occur it normally happens within 24 – 36 hours of the LH surge. We will discuss timing of ovulation in relation to the LH surge in more detail during Week 5.

The purpose of our menstrual cycle is to pass on our genes by conceiving a child with our sexual partner. To do this, a sperm from a male has to join with one of our eggs. The human egg when mature is the largest cell in the human body and is even visible with the naked eye at around 0.1mm in diameter. Inside the egg are 23 chromosomes – half of the DNA required for the growth of a new human (the other 23 chromosomes coming from the sperm).

The lifecycle of the human egg actually begins in the womb. By the time you are born you have around two million immature eggs (one million in each ovary). Each egg is housed within a tiny fluid-filled sac called a follicle. Because the follicles (and therefore the eggs inside them) go through a constant process of growth and death, this number will reduce to around 400,000 by the time you hit puberty.

Our existing understanding of female fertility is that women are born with all the eggs they will ever have. Some research suggests that women may be able to grow new eggs; however, this research is still in its infancy and is mainly focused on mice. At this point in our understanding, it’s very likely that by around 20 weeks’ gestation you already have all the eggs you will ever have. This means that the origins of half of your genetic material probably first existed when your mother was a foetus inside your grandmother’s uterus!

At any one point in time we have follicles at all different stages of growth within our ovaries. This is because the growth and death cycle of follicles is a constantly occurring process throughout our lifetime and throughout our menstrual cycle. This constant growth and death cycle is known as atresia. Each menstrual cycle, a group of around 10 follicles are chosen to continue their journey of growth. Out of these ten follicles, only one will become dominant to release an egg. It takes approximately three months for a follicle to grow to the point of ovulation – the ovarian cycle discussed below is just the part of growth that occurs during the menstrual cycle.

 

FOLLICULAR PHASE: After our period ends, a group of around 10 follicles begin to grow in your ovary. They are stimulated to start growing by a hormone called follicle stimulating hormone (FSH). Growing follicles produce the hormone oestrogen. As these follicles grow larger and larger, they produce more and more oestrogen which circulates in your bloodstream. Eventually, one follicle (the largest one) becomes dominant while the other follicles die off. This dominant follicle can grow in size up to 2cm in diameter! The dominant follicle releases peak levels of oestrogen into the bloodstream. This is why oestrogen is the dominant hormone of the follicular phase. Remember that oestrogen causes the lining of the uterus to grow.

OVULATION: Peak levels of oestrogen in the bloodstream eventually trigger a surge of luteinising hormone (LH). Luteinising hormone triggers the egg inside the dominant follicle to mature and then burst out of the follicle. This is the moment of ovulation! While we think of ovulation as a quick and explosive event, it actually takes around 15 minutes for the egg to emerge.

Once released, the egg is collected by the fimbriae of the nearest mobile fallopian tube. The cilia (hair-like projections) work to waft the egg deeper into the fallopian tube. If there are any sperm ready and waiting to fertilise the egg, this will happen in the outer third of the fallopian tube. The egg only has a very short lifespan (usually around 16 or 17 hours) but we round this up to 24 hours for the purposes of using the Symptothermal Method.

If any further eggs are released (as in the case of non-identical twins or triplets) they can only be released during the 24 hour lifespan of the first egg. This means that the maximum timespan that there could conceivably be a fertilisable egg waiting in the fallopian tubes is 48 hours each menstrual cycle.

LUTEAL PHASE: After ovulation, the follicle that the egg emerged from undergoes a transformation. The remaining cells of the follicle develop into a temporary structure known as a corpus luteum. Corpus luteum is Latin for ‘yellow body’ due to the yellowish colouring. The corpus luteum produces the hormone progesterone in large quantities. Progesterone causes the lining of the uterus to thicken and become very nutrient-rich in preparation for a potential pregnancy. Progesterone is the dominant hormone of the luteal phase.

The corpus luteum has a fixed lifespan of 10 – 16 days. If a pregnancy does not occur, the corpus luteum will begin to break down and stop producing progesterone. During the process of breaking down the corpus luteum progressively shrinks smaller and becomes known as a corpus albicans. Because progesterone (and some oestrogen) is necessary to sustain the thick endometrium, when these hormone levels drop the lining starts to slough away. This is menstruation, which happens 10 – 16 days after ovulation. During menstruation, levels of oestrogen and progesterone are at their lowest levels of the entire menstrual cycle.

If an egg is fertilised and implants into the uterine lining, the corpus luteum is ‘saved’ from breaking down. The early placental cells produce a hormone called human chorionic gonadotropin (hCG) which signals the corpus luteum to stay alive and continue producing progesterone until the placenta can take over in the second trimester. We will learn more about fertilisation, implantation and pregnancy later in the course.

During the menstrual cycle, the uterine lining (endometrium) cycles through three different phases:

1. Menstrual Phase
2. Proliferative Phase
3. Secretory Phase

THE MENSTRUAL PHASE

The menstrual phase of the uterine cycle is when the lining of our uterus (the endometrium) is sloughing away and exiting the body through the vagina. This is known as menstruation. Menstruation occurs when levels of progesterone and oestrogen fall below a certain threshold because pregnancy has not occurred. The process of menstruation is also helped by the release of prostaglandins – chemicals that have hormone-like effects in our bodies. Prostaglandins cause our uterine lining to contract (hello, period cramps!). Diet, lifestyle and environment are three of the largest contributors to menstrual cramping and discomfort.

Prostaglandins sometimes also affect our lower intestines meaning we’re more likely to experience cramping and loose stools while menstruating.

Different women will experience different durations of bleeding, but generally between 4 – 8 days is considered normal. There is also a wide range of acceptable blood loss, with anywhere between 5 – 80mL considered a normal amount by official standards. If you have concerns about the quantity of blood loss you experience, using a menstrual cup can provide an easy way to measure.

Menstrual bleeding is usually heaviest during the first two days and it’s normal to notice some clumps or clots. After these first few days the volume of blood loss usually lessens. You may notice the colour of your period changes from being brighter during days of heavier flow to a more rusty/brown colour on days of lighter and slower flow. This is due to a process called oxidisation – the longer it takes for the blood to reach your menstrual pad, the more chance there is for the blood to come into contact with oxygen which causes a change to a browner colour. You likely won’t notice oxidisation so much if you’re using a menstrual cup. Ideally, your period should be a fresh deep red colour and not overly light or heavy.

A note on periods: A true period is any bleeding that has been preceded by a successful ovulation 10 – 16 days prior. Bleeding that was not preceded by a successful ovulation is generally called a breakthrough bleed.

PROLIFERATIVE PHASE

After the menstrual phase, the endometrium rapidly begins to regenerate and grow again. This stage is known as the proliferative stage. The growth of the endometrium during this time is due to the hormone oestrogen. Oestrogen is produced by follicles inside the ovaries as they grow larger in preparation for ovulation. The larger the follicles, the more oestrogen is produced! The proliferative phase varies in length.

SECRETORY PHASE

After ovulation occurs, the endometrium enters into the secretory phase. The lining that previously regenerated starts to become thicker and very nutrient-dense in preparation for a potential pregnancy. This is caused by the hormone progesterone. Progesterone is produced in the ovaries after ovulation has occurred. If a pregnancy doesn’t happen during this phase, progesterone and oestrogen levels drop and the endometrium begins to break down. The secretory phase is a fixed length of 10 – 16 days. After this time, menstruation begins and the cycle starts all over again.

The primary purpose of our reproductive system is to pass on our genes (and those of our partners) by conceiving and birthing a child. The reproductive system is made up of external and internal anatomy.

External

Our external anatomy is known as the VULVA. It includes

MONS PUBIS: Mound of fatty tissue above the pubic bone.

CLITORIS: A ball of over 8,000 sensitive nerve endings – designed purely to provide pleasure. The clitoris is a much larger structure than we can see from the surface. Internally, the clitoris extends through and behind the labia – it is comprised of erectile tissue which swells with blood when we are aroused.

CLITORAL HOOD: A protective hood of skin that houses the clitoris.

URETHRAL OPENING: This is where urine is expelled after travelling from the bladder through the urethra.

VAGINAL OPENING: The vaginal opening is where the vaginal canal exits the body.

BARTHOLINS GLANDS: On each side of the base of the vagina are the Bartholins glands – two pea-sized glands that secrete lubricative fluid when we are sexually aroused. Allows for easier penetration by the penis.

PERINEUM: Area of smooth skin that connects the vulva to the anus.

LABIA MINORA: Inner vaginal lips. These vary widely between women. It is normal for the labia minora to extend past the lips of the labia majora, to be asymmetrical, to be of differing lengths, to be a different colour than the rest of the vulva, and even to be barely visible in some cases. All variations are normal.

LABIA MAJORA: The fatty tissue that encompasses the smaller labia minora.

 

Internal

VAGINA: The vagina is a muscular tube that connects our uterus to our vaginal opening. It can expand to accommodate a mans penis and even a baby during childbirth. It allows menstrual blood, cervical fluid and other vaginal discharge to exit the body.

CERVIX: The cervix is the lower 1/3 of the uterus and is approximately 3cm long. The internal os (internal opening) opens into the uterus, and the external os (opening) opens into the vagina. Ovarian hormones cause the cervix to lower or retreat higher into the vagina and change in openness and firmness at different points of the menstrual cycle. Ovarian hormones also cause the cervix to secrete different types of cervical fluid at different times of the menstrual cycle. These secretions are produced from crypts that line the internal passage of the cervix.

UTERUS: Shaped like an upside-down pear and situated between the bladder and the rectum. The uterus has an internal lining called the endometrium. Each menstrual cycle, the endometrium grows and thickens in response to ovarian hormones. If a pregnancy does not occur, the endometrium sloughs away as menstrual bleeding. In most women, the uterus is tilted slightly foward over the bladder. Around 20% of women have a retroverted uterus that tilts backward instead.

FALLOPIAN TUBES: The fallopian tubes extend out from each upper corner of the uterus toward the ovaries. They are mobile structures around 10cm long. They culminate in the FIMBRIAE which are groups of 10-15 finger-like projects that assist with collecting an egg from the ovary at ovulation. The fallopian tubes are lined with tiny hair-like projections called cilia. The cilia beat in a wavelike motion to help transport a fertilised egg toward the uterus where it can implant into the endometrium.

OVARIES: The ovaries are each connected to the uterus via the ovarian ligament. The ovaries are not connected to the fallopian tubes; however, the fimbriae hover very closely around the ovaries. The ovaries are a whitish colour and each around 3.5cm long (the size of an unshelled almond). The ovaries are the site of the development and release of an egg at ovulation, and the ovarian hormones oestrogen and progesterone.

Men are fertile from puberty until old age. Each day, men produce around 200 million sperm (100 million in each testicle). Once inside the reproductive tract sperm can survive up to 5-7 days (and even longer in some instances).

The male reproductive system is responsible for the production of sperm, and the delivery of this sperm into the female vagina. It is also responsible for the production of the hormone testosterone. Testosterone influences secondary sex characteristics such as facial, pubic and body hair, a deep voice, and bodymass composition.

PENIS: Shafts of spongy tissue that become erect during arousal due to increased blood flow. Around 3-4 inches long when flaccid, and 6-8 inches long when erect. Inside the penis is the urethra which transports urine out of the body. At the head of the penis is the glans which is a sensitive area covered by the protective foreskin. During erection, the foreskin retracts to expose the glans. The penis has around 4,000 nerve endings and is very sensitive.

TESTES (singular, testis): Each testis is home to the continuous growth and development of sperm. As sperm mature they migrate into the epididymis where they are stored until ejaculation. At ejaculation, approximately 250 million sperm are released. This release is relatively explosive, with the average speed of semen ejaculated from the penis clocking in at 45km/hr or 28mph! The process of sperm growth and development is known as spermatogenesis and takes around 3 months. The testes also secrete the hormone testosterone. The testes are housed in the scrotum which can lengthen and contract. This is to control the temperature of the testes and protect the growing sperm.

VAS DEFERENS: The vas deferens are tubes that transport sperm out of the man’s body at ejaculation. Sperm move from the epididymis through the vas deferens up and around the bladder, through the seminal vesical, through the prostate gland and on into the urethra. On the way, sperm receive different fluids from both the seminal vesicles and the prostate gland.

SEMINAL VESICLES: A pair of glands that produce alkaline fructose-rich fluid that empties into the prostate at ejaculation. Fructose provides energy for the sperm.

PROSTATE GLAND: A gland below the bladder that produces a zinc-rich fluid at ejaculation. This fluid protects the sperm from DNA damage on their journey.

COWPERS GLANDS: A pair of small pea sized glands on either side of the prostate. They deliver small amounts of lubricative fluid during sexual arousal. This fluid provides lubrication within the urethra and also provides lubrication for the penis entering the vagina.

SPERM: Sperm are the smallest cells in the human body. They are shaped like a tadpole with a head, a midpiece and a tail. In the head of the sperm are 23 chromosomes – half of the genetic material required to form a new human.

 

 

Understanding the foundational concepts of the menstrual cycle allows us to develop body literacy and use the Symptothermal Method more effectively.

While you’re probably familiar with your period, there is a lot more that goes on behind the scenes each menstrual cycle to result in your bleed. In fact, the main event of the menstrual cycle is actually ovulation – but it’s not visible to us from the outside so we’re not as familiar with it.

The two main events of the menstrual cycle are:

1. Menstruation (your period), and
2. Ovulation (the release of an egg from one of your ovaries)

Our menstrual cycles can be broken down into two main phases that are separated by the event of ovulation:

1. The follicular phase begins on the first day of your period and lasts up to and including the day of ovulation.
2. The luteal phase begins the day after ovulation and lasts until the day before your next period.

The follicular phase varies in length. The length of this phase varies between different women and between different menstrual cycles for the same woman. Basically, there are lots of things that can cause you to ovulate sooner or later than usual and hence change the length of the follicular phase.

The luteal phase is always a fixed length of anywhere between 10 – 16 days. This means your period always arrives 10 – 16 days after ovulation. The timing of ovulation is what determines the length of your menstrual cycle! In fact, we even have a saying “There’s no such thing as a late period, only a late ovulation!”

You may have heard it said that ovulation happens on ‘day 14’ of your menstrual cycle. This is just an ideal scenario based on a 28-day menstrual cycle. In reality, ovulation can occur earlier or much later than CD14 (even for someone with a 28 day menstrual cycle)! The only thing we know for certain is that our period will always follow 10 – 16 days after we finally ovulate.

The two main processes of the menstrual cycle are:

1. The cyclical thickening and release of the lining of your uterus (this lining is called the endometrium). The purpose of this cycle is to create a nourishing environment for a fertilised egg to implant.
2. The growth of groups of follicles and subsequent release of an egg from your ovaries. (Each egg is housed in a small follicle inside the ovary).

If the egg we release at ovulation is not fertilized, the lining of the uterus will break down and exit the body through the vagina. This is our period – and it is the culmination of the events of the previous menstrual cycle.

The first day of a new menstrual cycle is the first day of fresh red bleeding on your period. We call this day ‘Cycle Day 1’.

Ovarian hormones
During the menstrual cycle, our ovaries also produce the hormones oestrogen and progesterone. Oestrogen is produced during the follicular phase due to the growth of follicles in our ovaries. Progesterone is produced in the luteal phase, after an egg is released from the dominant follicle.

Oestrogen is the dominant hormone of the follicular phase, and progesterone is the dominant hormone of the luteal phase.

We’ll learn more about the processes of egg growth and uterine-lining growth in the next lesson. Plus, we’ll start to delve into the hormonal cycles that make all of these processes possible.