Preeclampsia | Reproductive system physiology | NCLEX-RN | Khan Academy

Preeclampsia | Reproductive system physiology | NCLEX-RN | Khan Academy

– [Voiceover] Okay, so I want
to start off with a scale. So this is a scale, a time scale. And on this end is before pregnancy, and on this end is after pregnancy, and then in the middle is the
20-week point of pregnancy. And I want to use this scale
to show you how different pregnancy related hypertensive
disorders are split, because they’re split up according to when the hypertension occurs and also according to how severe it is. So starting on this end, let’s say a woman has had high blood
pressure for several years before she became pregnant, or if she’s found out to
have high blood pressure before 20 weeks into her pregnancy, then we say that she has chronic, she has chronic or preexisting, chronic or preexisting hypertension. So, her hypertension has
nothing to do with pregnancy, because she either had it
before she became pregnant, or before the 20-week
point into her pregnancy. And this 20-week point
is important because before it, sort of in the
early stages of pregnancy, pregnancy reduces blood pressure. So if a woman is hypertensive
before the 20-week point, then the cause of her
hypertension has nothing to do with the pregnancy. Now, if instead she’s found
to have high blood pressure after the 20-week point in her pregnancy, we say that she has gestational, she has gestational hypertension. I’m just gonna abbreviate
hypertension as HTN throughout this video,
I’ll save a lot of time. Or, hypertension related to her pregnancy, that’s what gestational hypertension is. And typically, gestational
hypertension, usually, should resolve within 12
weeks of giving birth. If it doesn’t, then
chances are that the woman probably had high blood pressure before ever becoming pregnant,
but that we didn’t find it in the earlier stages
of pregnancy because of that physiologic lowering
of blood pressure that we were talking about that occurs early on in pregnancy. So, I guess you can say
that these two conditions, chronic hypertension and
gestational hypertension, are sort of the milder
forms of hypertension. So now let’s talk about the more serious hypertensive disorders,
which would have to be preeclampsia. Preeclampsia. Which is kinda spelled weird, preeclampsia and eclampsia. Preeclampsia and eclampsia. So preeclampsia refers
to when a woman develops high blood pressure after
20-weeks into the pregnancy. So kinda just like
gestational hypertension, but along with a few other features. So in addition to the high blood pressure, there’s also protein
spilling into the urine, or proteinuria. Proteinuria. So protein in the urine. Or, there’s some other
form of end organ damage. And I’m gonna go through
exactly what that means in just a bit, but
there is some other form of end organ damage. Okay, so preeclampsia
refers to this constellation of high blood pressure,
proteinuria, and end organ damage. And eclampsia is when a
woman with preeclampsia develops seizures. Alright, so when a woman with preeclampsia develops seizures,
that’s called eclampsia. Alright. So it’s all good to know the
definition of preeclampsia, but why does it happen in the first place? Well, for as much as we don’t
know about this disease, we’re pretty certain that
a lot of it has to do with the abnormal development
of the blood vessels of the placenta early on in
the course of the pregnancy. So the blood vessels in the placenta just don’t develop correctly. Now if you remember, during
the formation of the placenta, the trophoblast cells of the embryo, which this is the embryo
and these green cells on the outside are the trophoblast. The trophoblast invade
through the decidua, which is what the endometrium is called during pregnancy. And they also invade through
part of the myometrium. And they do this, the trophoblast invade through the decidua so
that they can access and infiltrate the spiral arteries, which are the terminal
branches of the uterine artery. So they’re the arteries
that supply the uterus. So they infiltrate the
spiral arteries to get access to all of that oxygenated
blood that’s inside them. And that’s how the placenta
forms into this bed where blood exchange between
mom and fetus can occur. It’s because of this first
step of the trophoblast invading into the spiral arteries. Now in order for this
to happen successfully, I guess you could say two things
really have to take place. Two things have to happen. Firstly, the trophoblast
have to be pretty aggressive in their infiltration, they really have to dig into the decidua. And secondly, the spiral arteries have to remodel themselves. They have to go from being these narrow, thick-walled
blood vessels to sort of being these large, kind of
tortuous, vascular channels that allow a large amount of
blood to flow through them. So both things have to happen. And we think that preeclampsia occurs when they don’t. So the trophoblast do a bad job of digging into the decidua
and the spiral arteries just don’t change enough to allow for the increased blood flow. So let’s sort of take a step back and look at the big picture. If the placenta can’t gain good access to the spiral arteries, what that means is a poor oxygen supply to the placenta, which becomes more and more of an issue as the woman gets further
into her pregnancy and the fetus and the
placenta require increasing amounts of blood and oxygen. So the shortage in oxygen supply makes the surrounding cells
of the placenta really angry. That’s a really common
theme in the human body. When cells don’t get enough
oxygen, they get angry and they release molecules,
usually inflammatory molecules. And that’s exactly what happens here. The placenta releases several factors that enter mom’s bloodstream. And the factors start altering the way her circulatory system works, specifically the factors start damaging the cells that line the inside of the blood vessels, the endothelial cells. So if this is a blood vessel, we’re looking at it head on, it’s a cross-section of a blood vessel, we’re talking about these
cells on the inside. These really thin cells
called the endothelial cells that line the inside of the blood vessels. These cells are the
target of those factors that are released by the placenta. These are the cells that get damaged. And the damage of the endothelial cells leads to those characteristic
signs and symptoms of preeclampsia. So, for example, when the
endothelial cells are damaged, they lose the ability to control the tone of the blood vessels. So it becomes harder for
the blood vessels to relax and that’s what leads to
the high blood pressure. The blood vessels aren’t able to relax, that’s why you end up with hypertension. And the factors released by the placenta also cause the endothelial
cells to become more leaky. And these leaky blood
vessels allow protein to escape from them. And so when that leakiness occurs in the blood vessels of
the kidney, let’s say, and protein leaks out from
the glomerular capillaries, you end up with protein in
your urine, or proteinuria, which is one of the
hallmarks of preeclampsia. And throughout the rest of the body, when protein escapes
from the blood vessels into the surrounding tissues, right? And if you remember anything
about Starling’s forces, I know I’m asking you to dig
pretty deep with this one, you’ll remember that wherever
protein goes, water goes. So water follows the
protein into the tissues and you end up with edema or swelling throughout the body. So swelling in the face and the hands, and really swelling
outside of what you see in normal pregnancy. And the blood vessels
in pretty much any organ can be affected, leading to
whole body signs and symptoms. So, for example, you can have headaches, you can see headaches, seizures. You can see headaches, seizures, and also visual symptoms. So you can see visual symptoms from the dysfunction of the
blood vessels in the brain. You can also have epigastric pain, so pain in kind of that upper
middle region of the belly, and elevated liver enzymes. Elevated liver enzymes from
dysfunction of the liver. And you can also have
fetal growth restriction, so the fetus isn’t growing enough from dysfunction of the blood vessels in the placenta. So that’s what I meant by organ damage in the beginning of this video. Also, another key point
that I’d like to make is that the endothelial
cells, when they’re damaged, they can release their own factors. So, the factors they
release promote clotting, leading to clots
throughout the entire body. And as you can imagine,
that becomes its own separate, huge issue. Now, the diagnosis of
preeclampsia involves looking for all of these features
that I just talked about. So in order to make the diagnosis, a woman needs to have high blood pressure, so a systolic blood
pressure of more than 140, a diastolic blood pressure more than 90. That’s the general
definition of hypertension. And she has to have one
of the following criteria. She either has to have
evidence of proteinuria or she has to have some
evidence of end organ damage. So she could have elevated liver enzymes that indicate liver dysfunction, or she could have an increased creatinine, which alludes to kidney damage. Or decreased platelets,
which hint clot formation. Any sign of end organ damage
will make this diagnosis. And if you’ve ever spent much time on a ob/gyn floor in a hospital, you know that we screen for this disorder pretty aggressively because preeclampsia can have some really
serious complications. It can lead to placental abruption. It can lead to a liver
hematoma or rupture. It can also lead to something called disseminated intravascular coagulation, which really just refers to clots forming in the vessels all throughout the body. It can also lead to stroke
and even lead to the need for mechanical ventilation. So it’s a really serious, it can be a really serious disorder. So how do you cure this
seemingly serious disease? Well, really delivery is the only cure. Which makes sense, since the placenta is the source of all of these factors that are damaging mom’s vascular system. So removal of the placenta
should cure the diesease and it does. Delivery of the placenta always results in complete resolution
of the signs and symptoms of preeclampsia. Now of course it’s important to consider whether the fetus is mature enough to survive the delivery. So for that reason, if
a woman is past 37 weeks into her pregnancy,
then we usually procede with delivery if the mom has preeclampsia, regardless of how severe it is. If the pregnancy, however,
has not yet reached 37 weeks, then we usually only deliver if the preeclampsia is severe. Now one last point that I’d like to make, eclampsia, or seizures in a
woman who has preeclampsia, is one of the most feared complications of preeclampsia and the
greatest risk for eclampsia is just before delivery, during labor, and 24 hours after delivery. So for that reason, every
woman with preeclampsia is started on magnesium sulfate. So every woman with preeclampsia is started on magnesium sulfate, which is an anti-epileptic agent, or an agent that prevents slash terminates seizures. And the magnesium is given during labor and is continued for 24 hours postpartum, sort of to prevent those
seizures from happening. And it’s also important to
manage the hypertension. You can’t just leave the woman
with high blood pressures while she’s pregnant. So we can use drugs such as hydralazine. Drugs such as hydralazine and labetalol. And labetalol. So hydralazine and labetalol are safe antihypertensives
to use in pregnancy. Alright, so those are some details about a pretty feared
complication of pregnancy. Preeclampsia.

100 Replies to “Preeclampsia | Reproductive system physiology | NCLEX-RN | Khan Academy”

  1. This video was an extremely helpful tool for a new Labor and Delivery nurse. Thank you so much for this much needed and well explained video!

  2. thank you so much for this video! I'm studying for the NCLEX and this has helped so much in understanding preeclampsia

  3. thank u so much for this lecture… & its only in 14 mins … I learned so much within dis short period…

  4. Very good lecture! Nitpicking I know, but you probably the Starling Equation. Starling law is regarding the heart. It is also interesting if MgSo4 is used in every woman with preeclampsia in the US. In Norway it is only used if the preeclampsia is rapid, and severe. Thanks

  5. Great and understandable information. My wife just had early delivery due to seizures of HELLP and this video explained us what was the root cause after all.

  6. FINALLY i know why i developed preeclampsia!! no one who ever explain it to me!! i had it so bad that me and me son almost died. i also died a second time when u had post-preeclampisa!

  7. This was A LOT of great info and the diagram helped a lot! Thanks!

    Kelsie Spears


  8. You're a blessing. Thank you sooo much for sharing your knowledge with others. I just started in Labor and Delivery. This lecture is so helpful for a visual learner.

  9. What about postpartum pre eclampsia. I had severe postpartum preeclampsia 4 days postpartum with elevated liver enzymes, severe hyperreflexia and NO protein in my urine. They called it Atypical preeclampsia. Genetic factor for me, my mother had eclampsia with NO protenuria and only mildly elevated Bp. Preeclampsia is a multi organ disease so don't be fooled by the lack of protein!

  10. Thank you. Extremely informative. Our doctor gave us very little information about this after telling my wife that she had it. Thank you thank you thank you

  11. Thank you SO much for this video!! It is incredibly informative! I was able to learn so much without being drowned in medical terms! #birthinglittlehumans

  12. Really great videos i hope you make a french version of all of your videos … i know it's much but it would very helpful

  13. Excellent video as usual however, new research states that delivery dies not cure preeclampsia as previously thought. Moms are at risk for up to 6 weeks postpartum. AGOC released new protocols in 2013.

  14. wow very good ! even Ten Teachers Obstetrics textbook does not provide explanation as easy as this despite being the bible for obgyn! Thanks for saying my time !

  15. This was simply awesome. Elegant, comprehensive and just a pleasure to watch. Thank you so much ๐Ÿ™‚

  16. Wow, amazing video to get whole information about gestational hypertension. I do not need to read a whole book to spend hours to try to understand. Thank you so much, please make more a video like this. Also, she is so calm, smooth, knowledgeable. 5 star

  17. Not every women with pre eclampsia is started on mgso4
    Most of the contents of this video is wrong
    Also the drug of choice is not hydralazine

  18. The placental factors mentioned which are responsible for all these events are: 1.VEGF antagonist and 2.TGF-beta antagonist.

  19. Does every woman with pre eclampsia in the USA receive MgSO4 in labour, regardless of the severity of her pre eclampsia? In Australia and in The Netherlands we give it to women who show signs of cerebral irritation such as brisk reflexes with clonus. Interestingto see the differences in management in different countries

  20. Wonderful teaching! It is my dream to work in labour and delivery so I love learning about this stuff, I am currently an RPN. I know I need my bachelors and to write my RN to work in L&D but this may help me for the future! All the concepts explained here were very easy for me to understand.

  21. Mag sulfate is **not universally recommended by ACOG for women under 160/110. So "always given magnesium" is misleading

  22. In the history taking for the development of Pre-eclampsia :ย  Pre-eclampsia may come from the mother in law of the woman who is pregnant – Probably pointing to the fact that it also has an auto-immune basis.

    X chromosomes have something to do with immunity – woman have 2 X chromosomes, this is probably one of the reasons why women are more likely to develop auto-immune diseases – for eg –

    Grave' s disease; Hashimoto's thyroditis; Multiple sclerosis; Myasthenia Gravis; Systemic Lupus Erythematosus(SLE)(Lupus); Rheumatoid arthritis; Sjรถgren's syndrome.

    It adds up because the husband of the woman who is pregnant has his X chromosome from his mother.

  23. Thank you for this succint description of preeclampsia
    and eclampsia. I has HELLP syndrome at 22 weeks and the doctors delivered my baby but they refused to save him because he was 22 weeks and had IUGR. They 100 % believed he would not survive. This happened three weeks ago and we had his funeral service yesterday. I have been tying to understand why this happened when I had no history of hypertension before pregnancy and not until my checkup at 22 weeks. The placenta was never studied so I donโ€™t know if the blood vessels were abnormal. And I was not tested for any placental factors. But I had every symptom of preeclampsia you described. I had a BMI of 29 before peeganancy. I gained four pounds by 21 weeks and gained 10 pounds by 22 weeks definitely from edema. I had incredible neck pain and stiffness since week 20. I had really bad lower ligament pain since 15 weeks. I felt bloaded right between my chestbone by my stomach throughout pregnancy. Everything was completely back to normal two weeks after delivery. Do you know what I can do to decrease my risk of abnormal placental formation and preeclampsia in the future?

  24. I'm confused.
    Is hypertension occurring to compensate for decreased O2 supply or is it purely a symptom of endothelial cell damage? just wondering in relation to treating hypertension, if it is a compensatory mechanism wouldn't it be harmful to lower the blood pressure as less blood would make it to the placenta? or is it a situation where we are trying to lower BP to avoid damage to mum but not cut off supply?

  25. Nice video! A note though, you state that preeclampsia always resolves with the delivery of the placenta, but there are in fact moms who develop preeclampsia postpartum as well. But overall very helpful! I work as an L&D nurse in Michigan and we see so much pre-E.

  26. This video was so easy to follow. I feel like I understand pre-eclampsia WAY better than ever before. Thank you!

  27. To the narrator. I learned so much from your lesson and maybe picked up a slight Canadian accent? Thank you for helping me to understand. Very informative and thorough. I've always heard about this condition but am currently living this with my daughter.

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