胎盘早剥

one of the most annoying things ever has to be when you're putting on a screen protector on a phone and you notice the bubble in it you guys know what I'm talking about it happens pretty much all of us there's this bubble where the screen protector isn't touching the screen of the phone and so the screen protector can't do its job it turns out this is really similar to what a placental abruption is so you've got the uterus and there's the fetus inside the uterus and there's a placenta which remember it is this pool of blood that has the oxygen and the nutrients that the fetus needs to grow and thrive and the pool of blood is supplied by uterine arteries which are juicy and plump during pregnancy now there aren't only three arteries and they aren't really this big but this is drawn this way for simplification so what I've tried to show with this diagram is that the placenta is really nicely sealed to the wall of the uterus and that's essential for the placenta to do its job but what can happen sometimes for for a variety of different reasons is that these uterine arteries here can tear they can actually rupture and the blood that's inside them will flow out and start to build up between the uterus and the placenta like this so this is kind of like that screen protector bubble that we were talking about earlier and at this point where the placenta isn't attached to the uterus anymore the placenta isn't receiving the oxygenated and the nutrient-rich blood anymore so it can't do its job of turning it around and providing it to the fetus so it turns out that this accumulation of blood can stay small it can it can stay limited or the bleeding can continue and the pressure from that blood can dissect through or it can tear through the seal between the placenta and the wall of the uterus causing the placenta to separate from the wall of the uterus and with that some of the blood can leak through the vagina which is usually how this condition is noticed the mom will have some vaginal bleeding now before we go any further let's talk a little bit about some nomenclature so when there's only a little accumulation of blood and it's hidden behind the placenta it's called the sealed abruption so concealed abruption and as you can imagine you don't get any vaginal bleeding with a concealed abruption right it's pretty much trapped behind the blood is trapped behind the placenta but when the blood has torn through the entire seal and the placenta is completely separated from the uterus it's called a complete abruption so getting back to some of the symptoms of abruption the first is vaginal bleeding vaginal bleeding that occurs late in the course of the pregnancy specifically after the 20 week mark and that's referred to as antepartum as antepartum bleeding and there are two main causes of antepartum bleeding one is placenta previa which presents with painless antepartum bleeding and the second is placental abruption which presents with painful very painful and two partum bleeding because as you can probably imagine the placenta shearing apart from the wall of the uterus to which it was pretty tightly attached is a painful process now in addition to painful vaginal bleeding the mom the patient also experiences urine contractions and to understand why this occurs why you experience uterine contractions you have to understand that the uterus is first and foremost a muscle and in this situation where blood is leaking from the uterine arteries the uterus tries to control the bleeding by doing what it knows best and that is to contract and the goal of these contractions is to squeeze down on these arteries that pass through the wall of the uterus to limit the amount of blood flowing through them and while it's a pretty effective way of controlling the bleeding it also has an unwanted side effect of sometimes pushing out the baby that is to say that these uterine contractions can sometimes lead to premature labor and while we're talking about the symptoms of placental abruption let's not forget what happens to the baby with the placenta being separated from its blood supply the fetus isn't receiving the oxygen that it needs so the fetus becomes can become asphyxiated and it can show with concerning tracings so usually that's referred to as non reassuring fetal heart tracings which is abbreviated this way and usually this constellation of symptoms is how placental abruption presents and it's really important to know and to understand these symptoms and it's because the diagnosis of placental abruption is primarily a clinical diagnosis so sure you can try to image the uterus and the placenta but during pregnancy you're pretty much restricted to the use of ultrasound because of the concern for harming the fetus with other imaging modalities and on ultrasound blood especially fresh blood and the placenta have a very similar appearance so that can make it difficult to diagnose an abruption with ultrasound that's not to say that it can't be done just that it can be difficult at times now in the case that that you do make a diagnosis diagnosis of abruption deciding what the next step is can be pretty complicated on one extreme end of the spectrum where mom and baby are both unstable delivery is usually the answer delivery is also usually chosen if the baby is past 34 36 weeks and is healthy enough healthy enough to survive outside the uterus on the other end of the spectrum if the abruption is really minor and both mom and baby are looking good and and the baby is too young to survive outside the womb alone we can usually monitor both mom and baby until delivery is a safe option so after having discussed all those features of abruption let's consider some of the causes of abruption remember that the endpoint of all these causes has to be the tearing or the rupture of the uterine arteries that's the ultimate cause of placental abruption so the one cause that always jumps out to me Strom I always remember trauma and I tried to do this animation thing to show how trauma causes abruption so if a pregnant woman is in a car accident or or any traumatic event really the uterus stays fixed it doesn't move because after all it's attached to your skeleton it's attached to other organs but that's not the case for the placenta and the baby so any trauma or any mechanical event can cause the placenta to shear away to stretch and rupture these uterine arteries which leads to bleeding and abruption now as much as I tend to remember trauma as being the main cause of abruption and you probably will too trauma turns out to be a pretty uncommon cause most abruption --zz are actually due to chronic processes long term processes that affect how blood vessels form early on in the course of the pregnancy so causes such as such as hypertension or high blood pressure smoking or cocaine use these conditions cause diseased blood vessels to form blood vessels that are fragile that are easily broken right that can lead to placental abruption so in a nutshell that is placental abruption