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 UW question 418  



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Author8 Posts
  #1

Hey guys,I would like to discuss that question.

There is a pregnant lady 32 weeks of gestation with bleeding. She has a history of placenta previa.

It is asked for the most likely cause of her bleeding. I took Placenta previa because of the increased risk after a previous placenta previa.

The correct answer is Abruptio because in the question stem there was a normal Ultrasound at 12 weeks gestation. But I thought the Ultrasound at 12 weeks can be normal and the placenta previa develops later when the placente grows bigger.

So in my Opinion a normal Ultrasound at 12 weeks gestation doesnt rule out aPlacenta previa at 32 weeks, what do you think about that?





  #2

USG done at 12 weeks will show a low lying placenta, although most low lying placentas will migrate towards the upper segment as pregnancy advances, i dont think u can call it normal.


  #3

OK thanks.

So one can keep in mind a normal US at 12 weeks practically excludes a placenta previa later in pregnancy.



  #4

yes.


  #5

remember ..abruption occur in 1% of all pregnancies...and placenta previa occurs in 0.5% of all pregnancies...so it is abruption which is the most common cause of late trimester bleeding not placenta previa...even previous history does increase the chance of placenta previa , chances of abruption are still greater than p previa...just like.....although blacks are more likely to have sickle cell disease....but the most common Anemia in pregnancy is still Iron deficiency Anemia..EVEN IN BLACKS...





  #6

jinxed131 wrote:
remember ..abruption occur in 1% of all pregnancies...and placenta previa occurs in 0.5% of all pregnancies...so it is abruption which is the most common cause of late trimester bleeding not placenta previa...even previous history does increase the chance of placenta previa , chances of abruption are still greater than p previa...just like.....although blacks are more likely to have sickle cell disease....but the most common Anemia in pregnancy is still Iron deficiency Anemia..EVEN IN BLACKS...





According to UW the risk of Placenta previa after previous PP is 4-8% so I would disagree with your first comment. Placenta previa is more common than abruptio in a patient wit previousplacenta previa.



  #7

agree with shumalia...

apidemiology helps too.


  #8

if at 12wks, the placenta is normal it will be normal lying throughout pregnancy cos it is initially usully low lying and then it advances up as pregnancy advances. so that rules out placenta previa in this question.





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