Jennifer Dunlop says, "Getting in late, maybe past the time for questions.
I was wondering if there are hormonal phenotypes that would predict whether a woman will have
a cycle without ovulating or simply lose her cycle altogether than under stress.
Does it relate to body fat?"
Why would a woman have no cycle?
Why would a woman have an anovulatory cycle?
Carrie: Remember, cortisol is very, very, very potent in the brain.
If the body perceives itself is under stress, whether it's physical, mental, emotional,
environmental, it doesn't matter, then reproduction is not its primary focus anymore.
I had been thinking this for a long time.
I didn't know how to eloquently say it and then Dr. [1:40:27] [Indiscernible] said it
on stage one day.
She said, "Ladies, whether you want to or not, I'm sorry, but you were put here to reproduce.
Biology is what you do."
Now obviously not all women do and a lot of women, in fact, are trying to avoid it, but
that's what the body is set up for.
When you were under a lot of stress and under body fat, under body weight falls in that
category, then your brain says, "This is a stressor.
This is not a good time to get pregnant.
I'm going to take away her ovulation and/or I'm going to make her cycle late and/or I'm
going to take her cycle away completely all together."
We hear that a lot with women who have gone through a lot of stress, job change, divorce,
death.
Sometimes it can even be like just flying time zone changes can be a huge one for changing
your cycle.
But definitely when you're under body weight, you don't make the hormone leptin like you
should.
Leptin is a big hormone for letting the brain know she's of a normal weight.
She can carry a baby safely in a healthy manner so go ahead and make her ovulate.
If you were underweight, then oftentimes the body says, "Nope.
Not healthy, not strong enough, not able enough.
Let's protect her.
Take away ovulation and/or take away the cycle completely."
Then when the body fat comes back up, you see this all the time in like gymnasts or
my CrossFitters who stopped CrossFit or my chronic marathon runners.
They'll stop it.
The stress goes down the way it goes up to a more perceived healthy weight by the brain
and then they can ovulate and have a period.
Regardless of having a baby as your end goal, it doesn't matter.
But that's how the brain works.
Chris: Yeah.
My model for understanding this is pretty similar.
I feel like fertility is largely regulated by the question of can I afford energetically
to invest in the 50,000 calories and making a baby, the commitment of 1,000 or 2,000 calories
a day in lactation.
Then on the long-term scale, we invest a lot in the success.
We're not E. coli.
We don't just like make a billion babies and see which one survives.
We make a huge energetic investment collectively in children.
If your stress hormones are high, that's saying, "Well, whatever we do have for energy, we
might have these more important things that come first that we have to deal with before
we can make that investment."
If we don't have enough energy, then it says the same thing on the opposite side of that
equation that we don't have enough energy to deal with whatever we might face right
now or in the long term.
I've seen a couple papers connecting anovulatory cycles to hypothyroidism.
I think that stress hormones are sort of on one side of this equation.
You mentioned leptin.
I would also put insulin and thyroid hormone on the other side, the side of saying we have
enough energy.
Stress hormones on the side of saying we don't have enough energy, maybe not because of an
energetic deficit but simply because they're signaling a stressful situation that demands
energy.
I think that body fat -- being underweight is a huge -- if you look at fertility rates,
there's some observational data where they just look at the BMI of male and female partners.
Basically like two underweight partners are going to be very infertile.
But then as you cross a certain BMI threshold, you start to see infertility happen again.
I think that's largely because of a resistance to insulin and leptin.
The energy is there, but now your defect is you're not perceiving it properly.
Yeah, very similar thoughts on that.
Jennifer adds, "It seems that I simply do not ovulate under stress, but others have
a delayed ovulation and a longer cycle."
It's probably just a variation in the same response, do you think?
Carrie: Yeah, I would think so.