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Miscarriage

A miscarriage is the involuntary loss of a pregnancy before the point of viability (< 24 weeks). It's broadly classified into:

  • Early - < 12 weeks (95% of miscarriages occur during this period)

  • Late - 12-24 weeks → < 12 weeks


Most are idiopathic or due to chromosomal abnormalities.


Presentation

  • PV Bleeding – usually light, but can be heavy

  • +/- Pain – usually mild cramp, but can be severe

  • Can be asymptomatic


It differs from an Ectopic pregnancy as the bleeding comes BEFORE the pain!


Types

Threatened:

  • Actually NOT a miscarriage, but there is a threat to miscarry

  • Presents with PV bleeding w/viable pregnancy

  • Closed cervical os

  • TVUS shows an intrauterine pregnancy


Inevitable:

  • Miscarriage is inevitably going to happen

  • Presents with PV bleeding + pain

  • Open cervical os

  • TVUS shows an intrauterine pregnancy


Complete:

  • Miscarriage has occurred and all the foetal tissue has spontaneously passed

  • Presents with PV bleeding + pain, which has settled down/resolved

  • Closed cervical os

  • TVUS shows:

    • Endometrial thickness <15mm and homogenous with normal echogenicity

    • No retained products of conception


Incomplete:

  • Miscarriage has occurred and all the foetal tissue has not spontaneously passed

  • Presents with PV bleeding + pain, which hasn't yet settled down/resolved

  • Open cervical os

  • TVUS shows:

    • Endometrial remains inhomogeneous with increased echogenicity

    • Retained products of conception

      • This increases the risk of infection (commonly endometritis, which present as 2º PPH), therefore needs to be managed quickly


N.B. A way to remember if the cervical os is open/closed is with this. "Open your I's" - Cervical os is open in Incomplete and Inevitable. The rest have a closed os.


Other types:

  • Missed - When baby dies in womb, but the pt doesn't have any symptoms of miscarriage, such as bleeding or pain.

  • Delayed miscarriage – Pregnancy is no longer viable, but there’s a delay to the miscarriage happening. Asymptomatic, or may have mild bleeding +/or cramp. The foetus crown-to-rump length (CRL) is > 7mm w/no cardiac activity.

  • Anembryonic miscarriage - Presence of gestational sac w/o a visible foetus. Asymptomatic, or may have mild bleeding +/or cramp.

  • Septic miscarriage – Miscarriage in presence of clinical signs of an intrauterine infection.

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Management:

1st line - Conservative, which is where we let the miscarriage occur naturally

  • Pros – Natural, No harm from drugs/anaesthesia/surgery, Most prefer it

  • Cons – Can take longer, Uncertainty and anxiety, Some prefer active treatment, Psychologically worse

    • This isn't an appropriate option when the patient is having heavy ongoing bleeding, signs of infection, or they'd prefer active treatment


Medical option - Misoprostol (Prostaglandin E1) 800mcg PV/PO. Mifepristone (anti-progesterone) may also be added.

  • Misoprostol works to induce uterine contractions and push the retained products out, as well as for cervical ripening (softens and dilates).

  • Pros – Mimics “natural” miscarriage, No harm from anaesthesia/surgery, Most prefer it

  • Cons – SE's (Diarrhoea, N+V), Might need a repeat dose, May not work (10%)


Surgical option - Manual vacuum aspiration (MVA) under LA, or Surgical evacuation under GA.

  • Anti-RhD prophylaxis has to be given to Rh -ve women

  • Pros – Quick, Usually easy and safe, MVA avoids GA risks, Control over timing

  • Cons – GA risk, risk of infection/uterine perforation/incomplete procedure

    • To reduce the risk of complications:

      • Misoprostol 400mcg is given 2 hours before

      • TVUS pre- and post-procedure to check the uterus is empty

      • Prophylactic antibiotics given


Recurrent Miscarriage:

This is defined as 3+ consecutive miscarriages. Risk factors include:

  • Older Maternal age and Paternal age

  • Previous miscarriage

  • Smoking/Caffeine

  • Raised BMI

  • Heavy alcohol


In most older women it's idiopathic, but an important cause to look out for is Antiphospholipid Syndrome (15%).


Antiphospholipid syndrome is where there's inhibition to trophoblastic function, therefore leading to local inflammation, and thrombosis of uteroplacental vasculature.

  • It's diagnosed by the presence of Lupus anticoagulant or Anticardiolipin antibody (2 +ve results 12 weeks apart)

  • Managed with Aspirin 75mg + LMWH (Reduces miscarriage rate by 54%)

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Other less common causes:

  • Chromosomal Rearrangements (2-5%)

  • Uterine Abnormalities (2-3%)

  • Cervical Incompetence

  • Hereditary Thrombophilia – Factor V Leiden, Protein S deficiency, Prothrombin (FII) gene mutation

  • Other - DM (Poor control), Untreated thyroid disease, PCOS, SLE



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