Colloquial Menstrual Cycle

An attempt to explain the menstrual cycle to someone whose background is not in Biology but had a question about birth control:


The Hypothalamus in your brain


sends signals to the Pituitary gland that sits above your eyes, pretty much

The Pituitary gland has 2 parts

1 part secretes the hormones our body uses

and the hormones have balancing effects in our reproductive system

some are high when others are low, then they switch when the timing is right

that's pretty much the idea

so

the part of the pituitary is called Anterior Pituitary

it secretes hormones: LH, FSH, and Inhibin

Hormone LH goes on to become Androgen, which is a precursor to Estrogen

so basically what happens when you have a period

the 1st day of your period is Day 0

FSH (the hormone) enters your ovaries

and it encourages the cells there to mature

for females

when we are embryos in the womb

our eggs aren't eggs yet

they are oocytes

and the oocytes become surrounded by a layer of cells

and they become known as primary follicles

and so the maturation of our eggs pause here, at primary follicles

when we are born

all of our eggs are stopped at the primary follicle stage

and they stay there

until we hit puberty

when we hit puberty and start having periods

each time we have a period

it's FSH encouraging our primary follicles to mature

they go from primary to secondary

and as they mature

they produce estrogen

the estrogen hormone has a negative feedback on LH from the Anterior Pituitary

meaning it hinders LH while FSH essentially produces more estrogen

but it does this for about 10 days

and a menstrual cycle is normally 28 days

so at halfway, it's 14 days

at 14 days

the primary follicles develop into secondary follicles

not just one of them, but a bunch of them

and then at 14 days

one of those secondary follicles will be the biggest

and so the one that is the most developed becomes the egg

and it pretty much shoots out of your ovary into the fallopian tube

that's why you get cramps

and so at 14 days, 1/2 way in your menstrual cycle

after the egg shoots off from your ovaries

the hormone levels in your ovaries start decreasing

the LH triggered ovulation (the egg being released)

and then once that happens

where the egg was sitting, it's now like empty cells missing the egg

and this is known as a Corpus Luteum

the Corpus Luteum actually starts producing its own hormones as well

it makes estrogen, inhibin, and then progresterone

so what happens is

The hormone Inhibin has a negative feedback (hindering) effect on FSH (the hormone that encouraged the follicles to mature into an egg)

and this happens because we don't need anymore eggs since one already left

and is waiting to be fertilized

the hormone Progresterone has a negative feedback effect on the growth hormone also released with FSH from Day 0

so then LH levels are also decreased

and decreased LH stimulates growth of the womb

it's to prepare for a baby

BUT

if not fertilization happens

then your body is like, okay, we don't need this stuff anymore

and so the Corpus Luteum degenerates and becomes kinda like leftover scar tissue

and so then the hormonal levels of progesterone decrease, meaning it doesn't inhibit growth hormone anymore

so that means Growth Hormone increases because nothing is hindering it anymore

and so it stimulates the follicles to grow again

meanwhile

no baby is being made

so the stuff prepared as food for the embryo

it sheds from our bodies

and that's why it's not just blood, but it's also blood and sugary stuff

bc it was going to be food for the embryo

and when no egg is fertilized, we don't need those hormones, and so the corpus luteum shrinks

and that bed off food sheds off from our endometrium

and we get our period

we're back to Day 0

where follicles start maturing again

so because everything is hormonally controlled

when you have unusual periods

they say to take birth control

because it's trying to encourage your body to be more regular to the 28 day cycle

and that's why you might have effects at first

but it's really going to take another cycle to help your body adjust

so as you're taking bc now

you are changing the hormone levels to try and control the cycle like this

so if you have the placebo pills left over even though you already started your period

you finish them because you're trying to tell your body what your period schedule needs to be

since it's irregular

does that make sense?

But at the same time

I would cross-check if you should continue placebo pills because you may only need to take 3 or 4 days of them

if your pack came with more

and then you can throw the rest of that pack away and start on a new pack

I'm not sure how yours is bc it's a different one and it's been a while since I've taken bc

my understanding of the placebo pills

is that you take them to give a break from the hormones since they have no hormones in them

so when you take a placebo, it's to give time for your period to start

so you prob only need to take 3 or 4 of them even if you already started your period

or you can take all of them, if your pack comes with more

it's pretty individual

but I think that's more a question for your doctor, who would know better



As a side note, understanding female reproduction and the menstrual cycle should really be something part of general sexual education when you're younger. It's complicated, so the younger we can be exposed to what really goes on in our bodies, the better decisions we can make because we have a better understanding about what everything means. My hope for the future is that teenagers can actually learn about what Male and Female Reproduction means because it was difficult for me to ingest the material later on since I never really had exposure to it before. If you find yourself confused about the details in Male and Female Reproduction, you are not alone! There are many of us!

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