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- You know, when most of
us think of pregnancy,

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we focus down here at
what's going on at the

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level of the uterus, but
a healthy pregnancy has

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a lot to do with a properly functioning

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pituitary gland up here in the brain.

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The pituitary gland makes the hormones

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that are essential for life,
and in pregnancy it grows.

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And not just by a little
but by close to 150%.

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A lot of that growth is due
to cells call lactotrophs.

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These cells in the pituitary gland called

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lactotrophs increasing in number.

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Lactotrophs are these cells that

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make a hormone called prolactin.

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They make this hormone called prolactin.

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Prolactin stimulates breast growth and

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milk production, so as you can imagine,

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it's really important during pregnancy.

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That's all good but the problem is

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that while the pituitary gland grows

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substantially during
pregnancy, the blood supply

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to the pituitary doesn't
increase by as much.

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That kind of looks like this where

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if this is a normal pituitary gland,

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this is what a normal
pituitary gland looks

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like, and this is its blood supply.

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In pregnancy, this gland is way bigger,

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is way bigger.

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But, its blood supply
isn't that much greater.

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Throughout the pregnancy,
I guess you can say that

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the pituitary gland is in
a really fragile state.

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It's only receiving as
much blood as it needs.

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No more than that.

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It's really pretty susceptible to being

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in a situation where its blood supply

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doesn't meet its requirements,

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which can lead to ischemia,
or a lack of oxygen supply.

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Eventually it can lead to death

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of the cells of the pituitary gland.

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That death of the cells
in the pituitary gland

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is referred to as Sheehan Syndrome.

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The topic of this video.

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When do we have to
worry about all of that?

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We have to worry about it in any

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case of excessive blood loss.

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Any sort of trauma
resulting in blood loss or

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in the case of postpartum hemorrhage,

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which refers to when you have

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an excessive blood loss during delivery.

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In those cases the pituitary gland isn't

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able to withstand that
loss in blood supply.

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In addition to that,
remember that whenever

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you have a loss of blood volume,

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whenever you have a loss of blood volume,

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the blood pressure in the body drops.

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The body responds to that
dip in blood pressure

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by clamping down on all
of the blood vessels,

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which is referred to as vasoconstriction.

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The body repsonds to the
dip in blood pressure

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by vasoconstricting to
increase the blood pressure.

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That clamping down on the blood vessels

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of the pituitary further
reduces the amount

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of blood that's going
into the pituitary gland.

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In situations of acute blood loss, again

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such as in trauma or a
postpartum hemorrhage,

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you can have death of the pituitary cells.

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What does that mean?

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Why is that significant if you

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have death of the pituitary cells?

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Firstly, keep in mind that this

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isn't an all or none type of picture.

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You can have death of

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a few, many, or all of the cells.

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Usually it's just the
lactotrophs that die.

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In which case you end up
with a prolactin deficiency.

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Because of that, if you
have a prolactin deficiency,

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the breasts will reduce in size

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and the mom isn't able to
breastfeed after delivery.

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Usually, this is actually how
this syndrome is discovered.

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The mom isn't able to breastfeed after

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delivery and that warrants
investigation into

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the cause of why that's happening.

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You can have the death of the lactotrophs.

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You can also have death of the cells

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that make hormones involved
in the reproductive axis.

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That could lead to a lack of menstruation

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or an inability to
regrow shaved pubic hair

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or axillary or underarm hair.

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Or less commonly but still possible,

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you can have loss of all of the cells

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of the pituitary gland and that could

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lead to symptoms of low thyroid hormone

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such as, weight gain, cold intolerant,

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and you can also have symptoms of

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cortisol deficiency which could lead to

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fatigue or feeling tired, or even

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life threatening low blood pressure.

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The main treatment for Sheehan Syndrome is

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replacing these hormones that you've lost

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at the levels that the body
would normally make them.

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We're getting better and better

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at preventing this disease
from occurring all together.

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Nowadays, we take simple measures to

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make sure that if the mom suffers,

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any form of acute blood loss, we replace

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that blood volume as quickly as we can.

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That's a little bit of
information on Sheehan Syndrome.