1st trimester bleeding

30 Mar
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obs & gynae stuff is something I rarely have to deal with. Where I worked they typically got shunted to the O&G folk so I’ve never felt I know what I’m doing. hence the rather basic notes

  • 20% have bleeding; 50% of these miscarry. NB see the SMARTEM episode on this which explains why this figure is wrong 
  • implantation bleeding is common, occurring about 5-6 weeks after LMP and is benign. Can be as heavy as (and frequently mistaken for) a normal period.
  • physical exam should include assessment of the cervical os (note that this has typically been done by the O&G folk in my short experience) as an open internal os implies an inevitable miscarriage
  • urine HCG is 99.4% sensitive but can be wrong in dilute urine
  • giving Rh prophylaxis seems a mess when it comes to threatened miscarriage (again not something I’ve ever had to do) but reassuring that you’ve 72 hrs to give it. (though again there’s big doubts over whether you need it all in early pregnancy)
  • low rates of rise of HCG suggest abnormal pregnancy (for us that means think ectopic)
    • single value of limited use.
    • half life of HCG in ectopic about 7 days; <1.4 in aborting IUPs
  • Ultrasound:
    • gestation sac earliest visible US sign (double ring sign) at 4.5 wks
    • yolk sac (within gestational sac) at 5 wks
    • embryonic cardiac activity from 6.5-8 wks.
  • septic abortion is polymicrobial therefore treat appropriately.

12 Replies to “1st trimester bleeding

  1. Great notes. O&G is something that’s always daunted me and something I certainly need to learn more about. Cheers for the post.

  2. Cheers Michael, I think there’ll be a lot more of these posts as I read through the big books and try to pull out the things I need to remember and didn’t already know.

  3. Hi Andy
    I have a few links for you. One of course is Broome Docs http://wacdocs.csp.uwa.edu.au/2011/11/ectopic-pregnancy-hcg-hiccups-some-older-evidence/

    My favourite rsource when looking at 1st trimester bleeds is Ultrasound Village – these guys have some simple, clinical, + US algorithms with pics of what you need to see.

    US imaging in early pregnancy is both easy and hard – it can be very easy, but misinterpretation of images can be disasterous.!

      • My biggest tip for learning US in 1st trimester. Poker face… you never know what you will see, and even less often how the woman / couple will react – sometimes completely the opposite. They either laugh or cry – but never seem to be what you think!

  4. Oh, and the image at the top of this is actually a transvaginal pic,
    This is a great technique to learn for the early pregnancy bleeders, but tougher to find models.
    Last year I helped to run a course and had to recruit models for “endocavity” scans.
    Funnily enough all the prostitutes in Broome at the time were Irish backpackers, and they all turned me down, despite generous cash offers – as it was ” too weird” to have a TV scan by a trained professional, yet it is cool to do the dance with a drunken sailor! What’s that about…

    • 1) Are transvaginal images really important or can you get away with transabdominal if you see what you need to? It would certainly make the whole procedure a lot more acceptable to everyone!

      2) how do you even start recruiting for “endocavity” scans… glad i wasn’t doing it

  5. 1) There’s a difference in what week you could se fetal heart rate / gestational sac / yolk sac, and the transvaginal is the better one (1-2w earlier). And the transabdominal is more dependent of a good positioning of the uterus and a filled bladder so less scans that can’t answer your question.

    /EM resident now on ob/g rotation

  6. Andy
    1) What Bjorn said. The true value of TV scan is in confirming IU pregnancy so that you can safely discharge the ?ectopic, happy she has a confirmed uterine pregnancy, where you will often be left head scratching after an abdominal scan – it can be frustrating when the bladder is empty or the uterus is hiding behind the bowels!

    2) I suggest the “personal ads” if you want to find a model. Actually the nursing students and my office nurse put their hands up. I reckon it is no where near as confronting as a PAp smear if done well

  7. One thing I learned on one of the deep dive lit review podcasts on this subject, was that when you find an IUP in the setting of 1sTMVB, 90% will go on to deliver normally. It’s been a reassuring stat to give to worried parents.

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